All this talk of a central authority brings up some of the reasons why people prefer bitcoin to fiat currencies in the first place.
For those users who wish to stay anonymous, online wallets will probably never be an ideal solution. Sooner or later, online wallet services will face legal requirements to have at least some kind of "traceability" regarding their users.
I don't actually see that as a problem, there will always be a tradeoff between security and anonymity. Those of us fortunate enough to be able to reveal their identity will have slightly better protection from evildoers. Those of us fortunate enough to stay completely anonymous will probably never be able to sue somebody who ran with their bitcoins. Some of us might want both, a secure, covered-by-insurance bitcoin "bank" account, as well as a wallet of dirty money
I think The phone applications are a much better route then the online service. As long as I can pay/receive money from my phone there is no need for instawallet, mybitcoin or any of them.
Agreed, they are a good alternative for some of the cash
purposes of online wallets. They are not an alternative to merchant or banking services, which online wallets may or may not offer.
It is also a step towards another important goal for more wide-spread adoption, being able to use them in physical stores.
Being able to accept bitcoins without the need to install any hard- or software at all is a major step towards wide-spread adoption, and online wallets offer just that.
Don't get me wrong here, i do not advertise online wallets as the
solution for everything, and i won't encourage anyone to use any of the momentarily existing online wallet services for anything but petty cash, but i am absolutely certain that online wallets will be the main means of using bitcoins for the average Joe in the near future, like it or not.