With vbox I don't think you can do that, nor with any other hypervisor delivering full virtualization. You could try with a paravirtualization, like Xen, and see if you can trick the OS
Note that I don't know if windows is supported as a paravirtualized guest.
I was a heavy user of plastic payments, then I found Google wallet to be so convinient and easy to use that I used it for almost all of my cards. Then I realized the privacy implications of using those, so now I've fallen back to use cash: I use my bank cards only on the ATM to withdraw cash, and ocassionally I use my CC on big purchases or online shopping only.
Crypto has never enticed me enough.
So you "self"host elsewhere?
Yes. Don't.