Sheesh, you're posting questions late!
The credit card is mainly an authentication token and a security measure for the hotel's finances.
It is your choice which method you use to pay the hotel fees. You tell the hotel at check-in how you want to pay. If you don't chose the credit card, it's not used for payment and hence there's no paperwork coming along.
One situation where the credit card would be used (and hence a bill marked "paid" sent to the owner or separate billing address) is when you don't show up at all and haven't canceled your reservation within the deadlines given in the booking portal. That way, the hotel can be sure to get some money for the room now not available for making real money anymore. So the billing address is only important if anything is actually paid with the credit card, which it won't if you pick another payment method.
From what I read, the "normal" room categories might have a big bed suited for two people, whereas the "twin" room categories are sure to have two separate beds, and both room types can be used for the accommodation of one or two adults, with the different pricing levels (and, based on two adults, you can negotiate with the hotel for an upgrade to three adults and an extra bed).