This is a misunderstanding of what I said, I agree that a 17k utility bill is most certainly a mistake.
But for example, if your autopay bills with direct access to your checking account total 2k/mo then it makes sense to limit the funds of that checking account to roughly that much, maybe a bit more incase of variance. If a utility tried to withdraw 17k from an account that only has 2.5k in it, it will not be able to do so (Overdraft "protection" can be turned off).
If there's a small buffer in the checking account, other bills should not cascade from one large anomaly in that case, because the bank won't hand out partial payments.
Yes, there are still risks with autopay, but they're greatly mitigated with a dedicated checking account for that specific purpose. Furthermore, forgetting to pay one of the several bills manually is a risk in and of itself. I'm just pointing out that setting up autopay doesn't necessarily mean giving unlimited access to one's funds.
