I would guess that great writers not only write exceedingly well, but can slide into the creative frame more easily. Or, perhaps they are better at not spending time out of it in the first place. For a number of years, I was living under the assumption that I was going to be an artist of some sort. Not everything was great at that time, but I miss the way that I was taking life in. Meaning was closer to the surface, and serendipity reared its head more often.
Writing fiction or nonfiction is hard. It is a different kind of hard than rocket science or lifting a bus with only your two hands. The first hurdle always seems to be the writing bit ... that is the daily, every day, write. And I think that is the meat of what these apps are meant to do. Think of them like bots or NPCs that help you grind in the RPG of life.