I think you might want to care because that's a basic requirement of any legal business (or non-profit) pretty much anywhere.
The service is also time-limited. Would you pay some amount for images to be hosted for a limited time? That seems like a perfectly valid decision.
It may not be feasible to accept anonymous payments or accept credit card payments without at least an email address.
Also, services like this must necessarily 'bundle' their specific products, e.g. hosting individual images in the case of this site. The transaction costs, e.g. credit card payment processing fees, preclude charging too small amounts.
Maybe it would be possible to avoid requiring an email address, but then I'd expect they'd have to use your credit card 'fingerprint' as an account/user identifier. But I'm skeptical that any credit card processors would allow that, especially given the possibility (and likelihood) that people will upload illegal images like child pornography.