I don't get the pick the muscles thing almost as much as I get the open source fitness thing.

I think this is geared more towards people doing bodybuilding splits, rather than fitness in general.

Personally, as someone that exercises but not for aesthetics, I think of strength training in terms of movements not muscles worked. So I'm thinking "press, pull, squat, hinge" not "chest, lats, glutes". Thinking of function and then doing fundamental compound movements just makes more sense to me, although I do sometimes need to hone in on a muscle for functional reasons -- like targeting the glute medius for opening up my kicks in my Muay Thai training.

Neither is more correct, they're just different approaches.

Agree, it seems like a mismatch of features and audience.

As someone who doesn't know much about working out or what exercises to do this sounds like a good app. I need help, but picking based on muscles is off. My thought and goals are not by muscle group, but losing weight or getting more toned.

Conversely, someone who knows what muscle groups they want to target, probably already has some sense of the exercises to target and thus less likely to need the app.