I like the idea of rounding up a purchase automatically and then saving the difference. I can definitely see more people saving this way. Setting up a reoccurring payment to a savings account is a cool idea, too.
The thing about rounding up the purchase to the nearest whole dollar, though, is that it not only has the advantage of putting something, if just cents, into your Vault/savings, it also has the bonus of making it easier to balance your checkbook with whole dollar amounts (that is still a thing, right?).
The buying crypto would be an added bonus if the fees were lower or actually non-existent, but I don't mind people making something for their work. :)