To store money in someone elses wallet if you did not need those services is/was a mistake.
Agreed, 110%. I'm still a "noob" in the BTC world, but the idea of handing over my meager wallet to a 3rd party immediately seemed stupid to me. It's a shame the wiki and some respectable people in the community recommended such a service. I would feel horrible....
I'm not sure what all the services were that mybitcoin offered, but they definitely can't change the fundamental characteristics of bitcoin. There is no way they can guarantee instant transfers from external accounts without simultaneously losing the guarantee that your funds are actually 100% available at any moment. They can "guarantee" instant transfers internally from mybitcoin->mybitcoin, but these transactions are reversible, unlike real bitcoin transactions.
I totally agree with your OP. I was just pointing out the potential benefits of a REPUTABLE bitcoin banking service.