Is Servo Auto trim for manual flyers?

In auto mode, the aircraft behaves strangely.

My friend said it’s because autotrim hasn’t been learned yet.

So I said the autotrim function is for manual mode flyers, not auto mode flyers.

Then my friend shared this link showing that servo autotrim works in auto mode:

He didn’t fly the aircraft in manual mode, so I think he misunderstands something.

Autotrim “works” in auto mode, but that means it “saves” the trim settings; it doesn’t mean that turning on autotrim will change servo behavior on auto mode.

Can anyone clarify if what I am saying is correct?

I tried to debate and explain it, but because they were very impressed with trim setting done by manual flyer before, so they didn’t hear my saying.