Okay, sure, it's a greatsword made of pure blackness named "Soulripper", and yeah, you constantly hear faint screaming when it's within line of sight, and maybe it tried to consume Dave's barbarian when he picked it up, but it's also a +6 greatsword with flametongue and dragonbane! It's not like we can sell it, so I might as well use it!

Ok, but if I don't then how will I reasonably justify being a chaos goblin?

Evil - "I'll fucking do it again."

If you know it's a cursed item, then the curse needs to be manageable enough to be tempting compared with the benefits. Most of the time, you can't know it's cursed without it being a famous item and having a good History check or similar. Identify won't reveal cursed items.

That being said, a lot of the really powerful cursed items are oftentimes worth it. Sometimes you really just need a powerful as fuck item.