Everyone knows what the word student means. To prove that you're a professional educator (or any other profession that depends heavily on BS), you have to come up with jargon, or new words for common things.
Student was such a nice word, too. One could be a student at any age, and it had such a hopeful, optimistic quality.
Compare the following conversations:
"What are you doing with yourself these days ?".
Oh, I'm a student at the University....; or, I'm studying ......".
to
"What are you doing these days ?
"Oh, I'm a learner at the ....?"
Learner falls flat, sounding institutionalized and dreary, as if there was nothing wonderful about the experience at all.