You're right, there is a demand. But I wouldn't necessarily say that just because there is a demand it is correct. For pure financial reasons, maybe..

Backing up your wallet say, three times, will leave you very secure. The problem is that people are relying on those online third parties too much nowadays. When someone like, Paypal, takes over a wide market, they then can basically implement any rule they would like and the clients must obey. That amount of power simply breeds control, along with more government intervention and regulations.

I know the demand is there, however I think the future is keeping the currency digital, while stepping out of the web, and third parties, as much as possible. That is one of my biggest excitements about Bitcoin, but sorry to say the web app idea kinda crushes most of the hopeful thoughts I would have about it