1. I was helping translate the word for the benefit of those unfamiliar with Yiddish, and giving it context.
But you pulled a nice switcheroo there when you changed the subject of the “betten”. You claimed it doesn’t mean the same as davening, but when you ask, beseach, demand of a human being something which is in Hashem’s realm, it’s problematic.
This is what the Rebbe is answering.
The answer doesn’t fit the question you claim he’s asking.
There’s a very simple answer to the question why you ask someone to daven on your behalf – perhaps that person has zechuyos you don’t, so his tefilos will be answered. It doesn’t replace your own tefilos, it’s in addition to your own tefilos. Atzmus umahus areingeshtelt in a guf doesn’t enter the equation unless the question was about beseaching, asking, demanding, i.e. davening to the person.