If that's what you want to do, that's nice and go ahead, maybe the app is the cheapest way to get to that point. My point is that people who use them should be aware of their limitations, and compare that with what they want to achieve.

PS: the weighted keyboard thing is actually important. You can get cheap weighted keyboards for less than 200$, maybe even less in second-hand market. A non-weighted keyboard will limit your playing a lot, even early on.