It works very well for fast pace action comics, and simple slice of life works. I find myself scrolling through large talking scenes because they're boring to read, but i think thats more about how its presented.
I find people who have insanity long scroll ccomics terrible because they don't have a break point to let me as a reader breath. But that is more of an issue with not understanding the format/medium on the part of the creator.
Edit: because its designed for a phone the engagement time is expected to be lessened vrs normal formats. You want to design your mobile game/comic to be able to provide brief periods of entertainment and long standing entertainment. Try to think of it in the context of mobile vrs pc gaming.