I think it's because what tech people do is objectively verifiable.

Did the thing the agent made do what it was supposed to do? Yes/No. There's no "mayyyybe" or feelings or opinions. If the sort algorithm doesn't sort it doesn't work.

But a secretary-agent for a non-techie is more about The Feels. It can summarize emails, "punch up" writing etc. But you can't measure whatever it outputs by anything except feels and opinions.