You need to have a reason to pay the price of React. Otherwise you're just being a sheep.
I say this using React and Material UI in a present project, from my perspective development for what is a pretty simple form UI is massively slowed down by using them.
Could have knocked out the whole site on my own in 1/2 the time using the 'old' stuff.
But now we've got a lovely loading spinner while it downloads everything it needs piecemeal and a bunch of basic browser functionality is broken, we've got 10x the amount of code, have to deal with a whole extra API layer and it's a nightmare to debug sitting there watching network calls instead of being able to step through the code in a proper debugger, brilliant stuff.
Completely worth it for that one datepicker we have.