On most sites (such as Coinbase) you must provide passport and id scan to even buy any bitcoins. Then you have to wait while they verify your credentials. So there is no anonymity at all and it's more hassle than purchasing something with your credit card. Well, you can use a mixing service but then you incur even more hassle and fees.

Realistically, to use bitcoins you have to buy it from a site (incurs fees), then create transactions to other bitcoin addresses (more fees) whose owners will have to someday convert their bitcoin to real currency (even more fees). It's not even competetive with bank transfers which costs me a flat fee of about 5€ to transfer funds using my banks internet portal to any other eu bank account.