I have zero game design experience other than messing around in the Source engine. But for me. Whilst I agree gameplay is the most important part of a game. Graphics and aesthetics are a definite close second.
If a game looks shit. I won't enjoy it. Simple as. I'll give it the benefit of the doubt if that game is 20 years old. But even then, the classics which are still good today usually hold up visually. And games which don't (Tomb Raider, Goldeneye ect) I don't enjoy as much.
I love how games look and is usually what I remember most about a game after playing it. Take
Darkest Dungeon. I fucking adore the art of that game. I looked into it because of how the games looks. And turns out the game plays really well.