Aren't there some banks that do something similar to this where all your financial assets are tied into one account: your HELOC. You have no checking or savings accounts, per se. All your income goes directly toward paying down your HELOC. If you need to buy anything, you borrow from your HELOC.

So the advantage is you never have "idle" savings. Your money is always "working for you" by keeping your principal balance as low as possible. The disadvantage is that it can be tempting for some people to tap further into their HELOC for frivolous spending.