We trim our cats nails because when we don't they keep getting stuck on things. They also just accept that being stuck is now their life without any complaint so sometimes it takes us hours to figure out one is now stuck to the sofa and just accepted it vs decided to sleep on the sofa.
This is my boy. He scratches all his posts, his scratchers, everything and is very good about it, but at a certain length he'll do his usual routine where he'll gently hook the edge of a blanket and lift it, and drop it to ask someone to tuck him in, and the blanket won't drop.
He also might catch a claw on the sofa or something. Time to clip claws!
I trim my cat's nails because they fight sometimes and I don't want anyone getting hurt. Also because I want them to be able to make biscuits on me if they want to without feeling like I'm getting stabbed.
The main reason is that if your home doesn't have good wooden things to scratch, then the claws will start curling and growing into paws. This is a serious health risk. Regular scratch posts and furniture is not enough. The best scratch post is an apple tree in your garden. But if you don't have one, then you need to clip the claws regularly.