I think the email signup actually works really well in this case, since it's not actually presented as 'email to signup,' the whole product is just 'send an ema

I think the email signup actually works really well in this case, since it's not actually presented as 'email to signup,' the whole product is just 'send an email and have it turned into a physical card.' As a user, you don't actually have to think about the drudgery of entering your password twice and pulling out your credit card until after you've already kinda committed to sending a card by actually writing it. And it works pretty nicely as a really simple asynchronous interface. Instead of watching an animated gif spin while the proof of your card is generated, you just get something to aprove in your email.