...ly speaking

Every now and then I see people using such phrases as technically speaking, politically speaking, etc
I also see the phrases in the Longman Active Dictionary.
However, my English teacher said the use of "...ly speaking" is just a rather clumsy way of saying: "from a .... perspective".
I was wondering what native speakers think?
Thanks.

Hello, hplv1561w: Your first example has little to do with technology or tools. Sometimes a sentence adverb, to which you refer, describe how someone is speaking rather than using an adjective to modify their "perspective."

I disagree with your teacher. "From a .... perspective" is an educated, formal way of saying something. That does not make "...ly speaking" clumsy.
However, I would suggest that "...ly" doesn't work all of the time, and in these circumstances it can sound clumsy. So, maybe your teacher is trying to ensure that you always say it correctly, by sticking to the reliable option.