Trouble is it's still not mainstream enough for everyone to start accepting it as a form of payment but that will change with time. For instance visit amazonbitcoin.com and see what happens!
Sure, I can buy some btc and go buy something with it in some places. But where is my incentive to do that, rather than just go use my credit card or an ACH transfer? Btc is not more convenient, it's not cheaper, and whatever gain in privacy there currently is will not survive a transition to mainstream usage...although the first two problems ensure that there never will be mainstream usage.