There's a lot of subjectivity involved when judging whether or not something is "good art"- especially in comics.
I'm hardly the first person to say this- but the question of whether a particular style of drawing is "good" depends on whether it is achieving what it set out to achieve. For example, you can usually tell if an artist is drawing an action-oriented series in a semi-realistic style, but struggling with accurate renditions of human anatomy. Since that makes the comic less effective at telling the story than it would have been otherwise, you could argue that this is "bad" art. But the same style and skill level with anatomy might be applied to a slice-of-life comic that relies primarily on comedic dialogue and still scenes- and be interpreted as "good" art because in this case, the artist's limitations aren't quite as obviously in conflict with their storytelling.
Of course it's great to aim at becoming a jack-of-all-trades- but realistically, all artists have their strengths and weaknesses. Some people draw fantastic architecture, cars, or robots, but struggle with the human form. Others (and this is quite common) love drawing characters, but avoid backgrounds at every possible opportunity. There are artists who are very good with anatomy but whose characters have a certain stiffness about the way they move and interact because they aren't sure how to depict believable emotions and mannerisms. And of course there are also artists whose work is very stylized and well suited to a particular genre or theme, but falls flat in other scenarios- for example, a horror artist who is used to detail-heavy inkwork trying their hand at something more minimalist and adorable.
I think you'll find (as I have) that most people who read comics but aren't studying art themselves usually have an intuition about whether the art style fits the theme. They judge whether the art is "good" or "bad" not by some objective metric of skill, but by that same intuition- the feeling that the art either works with the story, or it doesn't. The rest is window dressing.
Even when it comes to drawing people in for the first time- skill isn't necessarily what does it. You need art pieces with a "wow" factor. For example, when I've got a booth at a convention as an illustrator, I'll put out pieces that have the most detailed, over-the-top backgrounds. On their own these pieces doesn't represent my skill level all that well- drawing additional details isn't always harder- often it's just more tedious (I find it meditative). But people stop and stare and say "Wow I could never do that!" The pieces I'm most proud of- the ones that really did require years of honing my skills- don't get nearly as much attention.
