Valid address means can I give a relative's address in the US and still pay using a CC (talking about the digital download on 29th ofc)?
You can, i got a RANDOM USA address on internet to purchase from amazon. They don't validate. I paid with credit card, i don't think Amazon will send billing address to bank as i see big providers only need CC No, EXP Date and CVV2 to charge you. The smaller sites that use third party processing company will do fraud checking on billing address to avoid fraud/charge back. Even flipkart will accept credit card with out proper billing address.