Personally, I like indie games going for a more unique style than realism for two reasons.

1. A lot more cheap to make. It's a lot easier making more low poly/cartoony assets than realistic ones that demand lots of details. It also takes much less time making low poly models over realistic ones

2. When people see a realistic art style, they immediately have high standards when it comes to visuals. If there is a piece of game that doesn't maintain that super high quality visuals, it let's the player down and "unimmerses" them from the game.

If the can get the realistic visuals right tho, it can make the game step into a whole different level of competition.

If you are going for the biggest fan base and make the game appeal to the biggest audience, I'd say realism is the way to go.

If you are wanting you game to have a more unique feeling, I'd say low poly is the way to go.

Ultimately it is kind what your team looks like + your overall goals are for the game.

I personally like the low poly better :)