Hey this depends on who the merchant is and which country does he belong to, initially many were keen to accept it but due to their governments not approving bitcoins they don’t accept it now. Also I feel one should be careful when using bitcoins to pay sellers with zero reputation, here I would suggest you use PayPal. Hey Bitcoins cannot be banned or stopped governments do not have that kind of mechanism to stop it, they can only impose rules which can always be broken.
Well we can't expect majority of sellers to have that much confidence in transacting in btc yet. This is a pretty new technology and people needs to have time to become familiar with it. Especially after the 2018 debacle that stripped confidence from new and would-be users. Give it time. It's inevitable that technology will be embraced by everyone.