What's the point of fighting monsters in Zelda BotW?

As you mentioned, monsters are a source of potion ingredients as well as minor loot. While neither of these are an exceptional way to improve your wealth novice players may find shrines or combat with bosses too challenging. This is an easy and safe way to amass some wealth.

Players can also use these camps as practice. As I mentioned, for players who are new to gaming this is one of the safest ways to practice combat, learn the controls, or try out a new weapon or fighting style. While you may not find it personally worthwhile, other players might.

Lastly, the camps are for entertainment. If you want to experiment and see what is the wackiest chain of events you can create using a bomb or stasis this is a good place to do it. Plentiful non-challenging enemies can make for some entertaining fights.

The truth of the matter is not everybody plays using the same "optimized" methodology it appears you use. While you may find it important to only use the most efficient methods to acquire new gear or money, other players may not. When viewing it with this perspective, these camps serve as much as a source of entertainment as they do a challenge.

It's certainly possible to play through the game ignoring most of the monsters you encounter. However, there are certainly good rewards that can come from clearing them out.

1. Many monster camps are guarding a monster chest that contains a weapon or other rare item. The chest only unlocks once all monsters in the camp are defeated.

2. Even if the camp isn't guarding a chest, they usually have other resources nearby that are difficult to gather while monsters chase you. These resources include things like fish in nearby streams, ore deposits, or a set of weapons.

3. Sometimes the monsters are just annoying. I can't tell you how many times I stood still to enjoy the view or to get my bearings when suddenly I get hit in the face with a random Octorok spitball. Or a Lizalfos decided to chase me while I was chasing a Korok.

4. Sometimes killing monsters will save a nearby traveler. They'll thank you and give you a reward - usually some mid-to-high tier food. (Occasionally it will actually be a trap, and you'll be attacked by the Yiga clan instead... stay on your toes!)

5. Honestly, it just feels really good to beat the snot out of Ganon's minions. With the right combination of weapons, wiping out a whole camp can be super satisfying.

You need their drops for armour upgrades. While potion ingredients are a secondary, rather minor boost, you need to kill a lot of monsters in order to get the best armour.

• Bokoblin (78) - Hylian, Radiant, Soldier,
• Moblin (27) - Flamebreaker, Radiant, Soldier
• Lizalfos (174) - Desert Voe, Rubber, Snowquill, Soldier, Zora
• Keese (116) - Climbing, Desert Voe, Snowquill, Soldier
• Chuchu (87) - Desert Voe, Rubber, Snowquill, Soldier
• Octorok (5) - Snow Boots
• Guardian (15) - Ancient
• Hinox (34) - Fierce Deity, Soldier
• Moldulga (17) - Radiant, Sand Boots
• Lynel (33) - Barbarian, Fierce Deity, Radiant, Soldier

The number is based on rarest drop required. You may need more kills if you don't get enough of the other drops (esp. guardians). Note that the base tier of most monsters do not drop it so you'll probably still need to kill more than listed.

Silver/white tier also drop gems, which again help for upgrades and also selling for cash. You need to kill enough lower tiers for them to start spawning.

Once you've got all that then there's no need to keep engaging. Indeed, items become available (purchased indirectly with more monster parts) that make the main monsters (bokoblins, moblins, lizalfos and lynels) ignore you so you can more easily skip them.

In addition to the access to resources and items to upgrade your items as per Mage Xy and OrangeDog, the item drops that are useful for elixirs can also be exchanged for Mon at the Fang and Bone shop. This isn't an early game shop and requires you to complete a quest to access.

At this shop you can sell monster parts for Mon. Mon can be used to purchase items at his store most of which cannot be obtained elsewhere. The Mon-exclusive items are Masks (Bokoblin, Moblin, Lizaldos and Lynel), Dark Hood, Dark Tunic, Dark Trousers, and the Spring-Loaded Hammer. All these items have uses. The Hammer is also useful for completing the Hyrule Compendium should you not wish to buy its photo.

The only way to get Mon without killing monsters and selling their monster parts is with drops from dragons and guardians. Drops from dragons and guardians are more valuable and generally better used for other purposes such as armor upgrades.

https://zelda.fandom.com/wiki/Mon

While this doesn't apply to all monsters, it's worth noting that while monsters respawn; treasure chests don't.

So if you are the type of player who wants to clear an area, or complete as much of the game as you can, you will want to open every treasure chest you can, and in many cases that means needing to defeat monsters.

There are 2 types of chests to which this applies:

• Some treasure chests cannot be opened until all the monsters in the nearby camp are defeated. There is no way around this without fighting monsters.

• Other treasure chests are simply guarded by enemies, but defeating them is not a requirement. However, often you will be forced to at least fight or sneak your way through monsters to get the chest, even if you don't actually defeat them.

I fully agree that early on clearing out monsters is often a waste of equipment given BOTWs notorious weapon durability system. However things change as soon as you acquire the Master Sword, which is the only weapon in the game that lasts forever. It does "lose energy" after a while and you'll need to wait for 10 real life minutes for it to recharge, but that's good enough for periodically clearing out monster camps. So the optimal strategy is:

1. Keep grinding out shrines until you get to 13 hearts (requires a minimum of 40 shrines in total). You can spend some of the shrine orbs on stamina and later convert them back to hearts via the Horned Statue in Hateno village.
2. Acquire the Master Sword
3. Destroy all the enemy camps you want until the Master Sword loses charge
4. Do other stuff until it regains power
5. Come back to clearing out monster camps

Gaining Urbosa's Fury is another way of clearing out monsters but this comes later in the game than the Master Sword, depending on how you choose to play your quests.