from a reader standpoint, I understand why vertical scroll format has taken off, but from a creative standpoint, I will always prefer the page format.
Not only because it's what I grew up reading and spent well over 2 decades of my life getting used to, but because the vertical format simply allows the author a little too much freedom. By that I mean that when you have the freedom to put an entire screen's worth of space between one panel and the next, it's too easy for an author to stop thinking very hard about how those panels relate to each other.
When everything's kept up close and personal so to speak in page format, I am forced to actually think about and grapple with the relationship the panels have with one another, how I'm guiding my reader's eyes, and what those things are contributing to the story as a whole. It's easier to read vertical scroll on a phone, but I find I end up producing less than my best work when I try to make comics that way.