Lots of things, just like with any hardware and software, issues can happen and some of those can be fixed with software. Also new features, I have a Gulikit KK3 which has gotten a lot of new features and improvements since I received it (won it in a giveaway), it was already the best controller I have ever used and it’s awesome to see them still continue to improve it.
Wouldn’t be surprised if it could literally split you in two and I’m not sure whether that’s a good or bad answer, but I won’t kink shame.