They matter 100% to me and it kind of irks me how little a lot of artists seem to care about them these days, at least seemingly anyway. I see A LOT of what looks like fan art to me. Something people could make at home. Like Katys Prism cover or Tove Lo's album cover, for example.
Good album art or ones I find appealing typically make me want to listen to an artist more but I don't bad ones have ever really stopped me altho it does affect my feelings about the single/ep/album if I scroll by it. I don't buy physical outside of a few vinyl here and there so it hasn't stopped me from buying music (unless it's kpop cds, then it has)
It matters a lot actually, the eye wants something to enjoy too.
It's as simple as that.
When I saw Kesha's Warrior cover, it made me really hesitant to skip that album all together.
It might sound superficial but the imagery is a reflection of the material 90% of the time.
SO when it looks bad it gives you a major hint imo.
Then again, when an album has good album art then it can elevate an album immensely.
It makes the whole experience so much better tbh.