I’m just really excited to see this app in development
Is it ok if I use it for rock music? I sold my electric guitars but the genre on my acoustic calms me in a way I can’t get from anything else. 
You’re certainly welcome to use it to play whatever kind of music you like! It wasn’t exactly built for rock music, of course, but there are various strumming patterns that you can choose from which work for many (if not all) songs from rock and other genres.