Hey Andrew, thanks for stopping by and commenting. I can't speak for Ally (I've never used them—but geez indeed), but you're right that Schwab will require you to keep a US address on file (not P.O. box). But it's also not very hard to do, most mail scanning/forwarding services offering street addresses will do (Traveling Mailbox, VPM, ECM, etc). And according to the people at Schwab I've talked to, as long as you keep a US address on file they will assume you live there.
You're also right that there are better banks in the world. In most respects Schwab is quite an average US bank, except for a few things that I would argue are paramount for most digital nomad types: low (even negative) fees for international use including ATM withdrawals, plus being willing to FedEx you a card to anywhere in the world if you need a replacement.
What other banks do you think would be a better fit for digital nomads?