This looks like a really nicely put together resource, congrats!

I would be likely to sign up if I knew there was an option to export to a more established free flashcard engine (e.g. Anki), or at least to csv, say, for no other reasons than peace of mind and flexibility. I see in your FAQ that that is on the cards (hah!) so I will keep my eye on it and I think you will definitely get more buy-in when that is a working feature.

Excellent work and best wishes going forward!