Either way is fine tbh, the main thing to keep in mind is legibility: scroll format is what most people prefer in this era of smartphone reading because the screens are so small and your images are restricted to 940 pixels wide (on tapas, 800 on webtoons).
So like generally your text will need to be larger than it would if you were planning to print (or read on a larger computer screen as opposed to on a phone). Readers who don't bother to zoom in too might miss some of the neat detail that you've included in the upper right and left panels, for example.
That said, there's nothing wrong with doing traditional pages 
I uploaded my first comic that way and still managed to gather a fair amount of readers. That said, I'm planning for the next one to draw them as pages initially and then slice them up into vertical scroll for uploading. I want to make print copies someday, hence the pages, but also want to improve the reading experience on these apps. I definitely feel like a lot of my panels are kind of small/hard to read as is lol
