That's why I always have to laugh when I hear about such-and-such a company "now accepting bitcoin!". They don't get bitcoin, they get USD, so they don't care. Want to buy something from Overstock? Take your USD, buy some bitcoin, put it into your Coinbase account, Coinbase sends USD to Overstock. It's like buying an Amazon giftcard for yourself--just an extraneous step between your original USD and the USD that go to the merchant's account.
Astute observers will note that this is very similar to the credit card situation: Overstock does not accept USD, they accept Visa. (and MasterCard. etc.)
If I go to Europe and buy something with my Visa debit card, my account is denominated in USD, but they do some forex and the merchant gets Euro.
If I go to Overstock and buy something with my Coinbase wallte, my account is denominated in BTC, but they do some trading and the merchant gets USD.
Except you can use any bitcoin wallet so they accept bitcoin not coinbase. As absurd as it sounds when snapCard (a site that orders from other sites for you) first started they would only work with Coinbase. Enough customers complained that they had to offer a second option to accept bitcoin payments from anywhere.
Not necessarily. You can chose to receive Bitcoin directly although most companies opt to convert to USD instantly given Bitcoin's high volatility. If the volatility goes down, more companies will decide to keep their balance in Bitcoin.
