The problem is that comics are non-linear in nature. Their stories don't really "flow" into one another, and carry an active continuity, especially in the early days. Like, most comic book stories are a 6 to 10 issue event, followed by an immediate drop and return to status quo, with a few off-hand comments about what happened last arc, until the new arc starts.
Comics method of distribution is somewhat irritating as well, speaking from personal experience. Unless you picked up issue 1 you won't have the context outside of the first page narration box to know what's going on. Issues tend to not be available to you once the new ones come out, making getting full context difficult, as well as creating a need to make the issues disjointed from one another, in an attempt to continue to draw in new readers even if they missed issue 1.
Finally, comics in modern times are very, very, very, very, liberal when it comes to resetting their universes canon. Meaning that at any moment, the comic you read will not matter. Because its events will not have occured, and we'll be reading about a different universe all together next time. The multiverse means you have multiple incarnations of characters who you could be reading and not realize which event correspond to which issues. Big crossover events are spread over multiple issues of multiple comic book series, making getting the big picture really difficult. And many writers brought on can create a bad interpretation of a character, which can vary from issue to issue erratically.
Compared to manga's, where there tends to be 1 artist, 1 writer, and 1 story creators vision at work, which allows a more coherent and linear story to be told. Also, the practice of keeping the series avaliable in compilation form that doesn't cost an arm and a leg and is easily accessible to digital distribution. Or at least, this practice exists once a comic book is out of compilation-manga distribution such as Shonen Jump, which release new chapters of manga each issue which eventually get compiled into its own series of books.