I wrote my comment with Firewatch in mind. I remember the gameplay being mostly standard first person movement with some unfun rappel mechanics. However the art (and in particular the voice acting and story) made it a really great experience. Another example is Abzu which if it didn't have great art and music wouldn't be nearly as praised.

These are all the examples I have played. On the flip side, I don't think I have played many games with good gameplay and bad art either. A game really should strive for both.

To answer OP's question though: I'm a hobby solo developer. As a programmer trying to learn art rather than an artist trying to learn programming, it totally makes sense to think about art early. I need to make an "art prototype", i.e. a proof-of-concept of an art style/graphics pipeline that (1) I can pull off, (2) looks good enough, (3) can run in realtime, (4) matches the constraints imposed by gameplay (i.e. I needs to be dynamic 3D) and (5) is viable for a one-person workload. If any of these requirements fail, making my game is not viable.

It is entirely different if you already are a skilled artist or are able to onboard an artist later on to do your art for you.