What problem does this attempt to solve? Their slack example doesn't seem particularly pressing.
Useful new technologies don't always solve obvious problems. Sometimes a more fruitful way of thinking about them is to ask: what might this help enable? And especially considering this not just in terms of an isolated individual using it, but in terms of if it had broad uptake where lots of people were using it. Think of things like the introduction of cars, or the internet. Their actual effect on most people weren'…
Cars weren't released out of the blue by a well-funded startup as a half-baked MVP, they were built off of advances in industrial metallurgy, the invention of the engine, engineering used in trains and boats. Similarly, the internet didn't just happen - people first figured out electrical engineering, circuit boards, GUI's, COBOL and C++ and a myriad of other languages that made it possible to invent the internet.
I'm not saying that this online bank thingie is on that level yet. But for me, these kind of inventions are indicative of the death of institutional finance. The first step in destroying global finance as an institution is to whittle away at where the banks can make profit. Apps like Robin Hood have already helped to decentralize knowledge and participation in the stock market. Cryptocurrencies like Bitcoin have shown at least a proof of concept that you don't need central banks to have currency. Money transfer apps like TransferWise eliminate currency conversion profiteering. Now what happens when you make a front-end that can wire all of these ideas together? A cashless society? Maybe.