Technically they didn't put a price tag on the app, the $1 was github sponsor money, so the project was never really designed to make money.

The app itself (Midi editor with piano roll UI) looks great but is instantly made much less relevant if you just install Reaper (and actual DAW, free to try, available at the time all this was developed).

Cool thing, but the moral of the story is: release that toy thing you spent a few weeks on, it's as ready as it ever will be and maybe it'll grow with it's user base.