As for the first comment, I'm literally suggesting absolutely no account whatsoever, just keeping cash in a box or under your mattress or god knows where. No I don't think any reasonable person would ever do this, but nothing in any purge scenario is very reasonable.
That said, if in that world you're a broke college student, then one ATM and suddenly you can afford books and a parking pass at the very minimum, tuition if you're smart, then use the money in your account from your real job for food and life stuff the rest of the year.
To those who aren't big level criminals, they're just trying to get by, it could be worth it

No, but you can definitely get enough to live off for a year after maybe 4 or 5 ATMs and then do it all again next purge

You're all sitting here trying to figure out how to hide money within an account but no jury can prove how much cash you have on hand. Either fill your account then cash out, or just break into a physical ATM. It's not nearly as secure as the bank itself, and cash is much harder to trace after the fact.