Thanks for the suggestions! A few people are saying they were confused, so I'll put some more effort around that wording

The import dialog is unfortunately just the system dialog - I have some other apps using it and it's frequently something people are confused about. There's no real way around it though.

I'm still experimenting with the catalog. The app used to have a lot of links to places to get MIDI files from, but I just don't think it's something most people wanted to bother with. But that remains to be seen!