I was the opposite. I used it as a calculator, without adding any ebooks on top, but my professors were uneasy about it. Then I got a calculator to curb their anxiety.
I remember when calculators were the Forbidden Fruit because, according to maths teachers, we were "not going to be walking around with calculators in our pockets all the time."
For simple stuff, incl. calculus, I agree with them. This was for other courses, which prioritize methodical correctness rather than math knowledge, like physics and chemistry.