I have tried to sell myself on using functions (not pure functions though but ones that accept an object and modify it) but ultimately sticked to OO. I try to find the balance in-between, if something is processing heavy it's going to be a function, but if it does not do much by itself and relies on a lot of state, it's going to be a method in a class - which may call a function or a few.

The biggest benefit is the structure, you get an API that can control any aspect of the app out of the box without the need to redeclare stuff.