When I began to cover songs for YouTube, they all tended to be in the super pop-genre.. as in, smash-hit songs. My writing process was heavily influenced by this - I went from a more heavy punk rock style to straight up sugary-sweet pop.
Writing original songs is much, much harder (I think) because you only have yourself to conjure up EVERY single moment a listener is going to hear. It's a craft that goes directly from your brain to their ears. You can never be sure that what you're writing is gonna be good enough to keep a listener engaged and truly experience something. It's a shot in the dark.