No, they accept USD, or whatever fiat currency they specify, with a transaction processor like Bitpay converting BTC to fiat on the spot.
I think you missunderstand the meaning of the word 'accept'. From merriam-webster dictionary:
verb \ik-sept, ak- also ek-\
: to receive or take (something offered)
: to take (something) as payment
: to be able or designed to take or hold (something)
I think that it is clear that to 'accept' something as payment you don't need to hold it afterwars. You are free to convert it to something else or use it in any other way you see fit. To give you some example, few people would argue that steam, google play or blizzard online store is not accepting euros because they convert it to dollars after the purchase.