The project is dead, the app is dysfunctional, the features hidden behind the subscription are broken, and you'll only find that out after you purchased it.
User support doesn't seem to exist, there's been basically no peep for like the past 9 months, an the only thing alive around this is the stream of befuddled users finding their way to the support platforms just to be met with complete silence.
A real shame, but there's no actual excuse for having to pay to have this corpse rot in your library.