Described this way, this just seems like a tool to facilitate a fundamentally unhealthy way to think about your money. If you're thinking in terms of "How much can I spend today", you've already lost. (Unless, of course, you're 23, in which case your entire goal in life should be to sock away enough money that you never need to ask that question again in relation to food/rent/etc.)
I like the transaction searching capabilities shown in the demo, but I was hoping to see more info on how to do actual "banking" tasks. Can I initiate a wire transfer from an internet cafe in Laos? Can people send a check to an address in the US that automatically gets deposited in my account? That sort of thing. When these guys came on the scene, I got the impression that that was the kind of thing they'd be doing better than other banks. Frankly, sorting my past transactions just isn't a problem I desperately need to have solved.