I believe this is really just a personal preference thing. Yeah, there are some potential performance boosts, one example referenced in the docs here, but the React team themselves encourage people not to go rewriting class components to functions.
Personally, I prefer Function components for a few reasons:
- In my opinion, they are more readable and simple.
- Due to the 'stateless' nature of a function component putting hooks aside for now, they encourage good modular design patterns
- Custom Hooks allow a nice clean way to break out reusable functionality between components
- See the potential performance enhancements in the link above