...is generally much faster (after a little practice)...
The thing is, so is the whiz wheel. By the time you finish PPL, it's second nature and very quick. It's also very visual (you can see the vectors). I'm all for using tech where it makes life easier, but sometimes it's just easier doing things the so-called old fashioned way. And it's somehow quite satisfying.
With so many flying apps, I'm surprised there's room in the market for another. If you have email access, you probably have acces to SkyDemon. Thats tough competition.