Nothing wrong with jQuery if it suits your use case! Sometimes mutating the DOM directly is simpler and more maintainable.

IMO React is a response to a problem that not all websites have (complex state-dependent nested UIs). At a certain level of complexity it's worth it, at another level it's necessary, beyond that it's insufficient... but below that it can totally be unnecessary and more pain than it's worth :)

Go with what works for you and your team!