In Minecraft, how can I use Curse of Vanishing and Curse of Binding to my advantage in Singleplayer Hardcore Mode?

The curses are meant to be negative. The best use for them, if you want to apply them intentionally, is pranks, like dispensing a pumpkin with curse of binding onto someone who isn't wearing a helmet.

If your world is multiplayer and don't have keepInventory, then the Curse of Vanishing can be used on really good items you don't wan't your enemies to get their hands on, like a powerful sword/trident, or a map that leads to your secret base or something.

Obviously only use if you're not likely to get killed by mobs often and if you wouldn't have got back your items anyway.

Any item or weapon enchanted with Curse of Vanishing is going to vanish or disappear after a player dies in the game.

And the cursed item is terminated forever as it is difficult to recover it.

You can use this enchantment to trick your friends by applying this Curse onto their tools, which in turn is going to vanish their tools after they die.

Gamers can also use this Curse in the PvP servers as it can help them obliterate the items when they die in a battle, which is going to ensure that their weapons cannot be used against them after they die.

Moreover, mapmakers can use this Curse to make the adventure maps harder for the players.

But it is advised to avoid this Curse entirely and make sure not to enchant anything with it.