The executive branch is really not supposed to have complete unrestrained control over the entire federal government.

The point about AI isn't about efficiency, it's about accountability. This administration already has a huge accountability problem, and the AI is another layer of "Oh, that wasn't really me who did that thing I did." This isn't just cynicism, the current admin is incapable of taking responsibility for anything they've done wrong (and perfectly willing to take full responsibility for things other people have done right).