I keep thinking of the Maya Angelou quote: "At the end of the day people won't remember what you said or did, they will remember how you made them feel." I do think good RPG art should invoke feelings related to the game it appears in. My gold standard for art is Thirsty Sword Lesbians, a game I have zero interest in playing, but when I look at the art it's very romantic in that it inspiring and really focuses on the individuals. It's exactly the right art for a game about "telling queer stories with friends" and "angsty disaster lesbians with swords."
That's the kind of thing I want to see in RPG art. Something that invokes feelings for a setting, a character, a monster, etc., etc.