It's not really true that everyone only uses these two, but whatever, I get that they're the most popular. For comics specifically, Clip Studio Paint is definitely the more obvious choice between the two. It has tools built specifically for comics: page management, speech bubbles for dialogue, manga effects, ready-made patterns. Procreate is fantastic for illustration and painting, but for actual comics you have to put in way more manual work. If your goal is to make comics from scratch, it's not the ideal tool.
That said, it also depends on what you mean by "comics." If you want to make something more artistic and painterly, like high-end comics or heavily illustrated graphic novels, Procreate could work just fine for you. But if you're thinking of comics with structured pages, regular panels and integrated text, then Clip Studio Paint really saves you a ton of tedious manual labor. With it you draw the panel, it creates the grid for you, and you add the speech bubbles in seconds.
The only real downside of Clip is the higher purchase price compared to Procreate, but considering how much time and frustration you save when you're working on actual comics, I'd say it's worth it. Feel free to try the trial version of both before you decide, but if production speed matters, Clip wins hands down for comics work.