Whatbox (and a few other seedbox companies) offer seedboxes in the US. How can they do that without being immediately shut down? Do they have some kind of restrictions that could cause problems with using a US-hosted seedbox?
AFAIK they do honor DMCA removal requests so if you happen to load a public torrent there & receive a notice Whatbox staff will ask you to delete that data. You could contact their support on that if you’re not sure on their procedure.
How safe is paying via your real payment details?
I’ve only used crypto for those things. But presumably if you find a pre-paid credit card they accept you could buy it with cash & then pay the seedbox provider with that.
How safe is connecting via your real IP
The seedbox service itself is essentially a VPN so you either trust it, or you don’t. You could just as well ask how safe is it to connect to your VPN, or if you need to use another VPN to connect to your VPN :P
One thing to keep in mind is that seedbox services probably do log more data than the typical no-log VPN.