Although, it probably would been nice if there were proper translations to non-Japanese languages, especially if they expect to sell to non-Japanese people and threaten Akiba-Online with a DMCA notice. But whatever. Good luck to their business, I am sure they are swimming in money now that low quality versions of their videos are no longer shared on Akiba Online.
I think websites today usually don't process credit cards themselves, often it is a third party such as Moneris so if that is the case I am not sure if they would even know your credit card.
Edit: Btw, I didn't know KV offered MP4 download. DRM-free? I never bothered watched them so I didn't know. Their videos aren't very interesting, to be honest.
Ah sorry, ignore my post, maybe I don't know what I'm talking about. Sometimes I see website use Moneris or Paypal to process credit card. But I haven't really paid attention and haven't used credit card often online recently.