The question is not whether to keep a human in the loop. It is which loop, and at which step. Put a person in front of everything and you have rebuilt the bottleneck you were trying to remove. Put them nowhere and you find out about problems from your customers.
A workable rule: automation can read anything, write internally without asking, and act externally only where the action is reversible. Drafting a reply is reversible. Sending it is not. Updating a record is reversible. Issuing a refund is not.
That line moves as trust accrues. A workflow that has run clean for a month on internal drafts has earned the right to send the routine ones on its own, with the unusual ones still routed to a person. What matters is that the line moves deliberately, after looking at the log, rather than drifting because approving things got tedious.
The other half is making approval cheap. If reviewing an item takes as long as doing it by hand, people will rubber-stamp, and a rubber-stamped approval is worse than no approval because it looks like oversight. Approval screens should show the decision, the evidence behind it, and one button.