Best uses for a twist-lock carabiner

You could consider using a twist lock where you would normally use a non-locking snap-gate or wire-gate karabiner but want just a little more security. An example could be on a quickdraw to use on a key runner where you would have used a normal quickdraw in the past.

I would consider this an advanced technique; the downside of this suggestion is that your climbing partner might not understand the role of the twist lock and use it in a crucial situation without realising. With an experienced partner that you trust this might not be a problem but would it come off your rack when you met a new partner?

Related: Why are twist-lock karabiners considered dangerous?

Nobody ever complained of having too many carabiners; you did not waste your money no matter what you do with it right now. Clip it to a stopper knot on the end of your reserve/back-up rope, or use it to keep a rope bag closed, or clip it to a tie-down or tow rope in the back of your truck. One day it will be exactly the piece you need at exactly the right time.

I've used a twist lock carabiner to secure a water bottle holder or glasses case to a bag. When travelling in a city, this prevents opportunist thieves from easily unhooking the item from my bag.