Totally agree with your critique, and your point on needing a good website (I bank with Smile Bank in the UK, who have not changed their site design in 11 years - and it is still (IMO) the best bank website design out there).
But what aspect of the existing currency exchange markets makes you think that doing a "billion" (or any other extremely high number) trades per day allows you to break-even only taking 1c per trade?
True, 1cent might not be enough, but the basic idea of just sitting in the middle of a large number of trades and skimming a tiny bit off the top is what a number of banks already do.
But what aspect of the existing currency exchange markets makes you think that doing a "billion" (or any other extremely high number) trades per day allows you to break-even only taking 1c per trade?