For example, students in one nation may only be memorizing button sequences, so are lost on the fundamentals, while those in another learn the fundamentals, then use the calculators to help improve their understanding.
Yes, it probably is, and for that I agree with c4757p - I somehow was thinking we were talking about university students, but then I realized the education system here in the US is different.
Back in Brazil up to high school (inclusive) no calculators could be used in any tests, and this forced us to do math by hand. At the university some teachers quickly realized the capabilities of advanced calculators and had a normal apprehension over the learning experience - one of them even disallowed "alphanumeric calculators"... Over time me and my colleagues showed the teachers this was really a wonderful helper for day-to-day activities (we programmed EE solvers of several types, Bode plots, root locus graphs, etc.)
When I was growing up we had a type of calculator that required you to insert the entire expression and gave just a right/wrong answer (green/red LED) and it was really fun to play with. Its name was "professor dismaquinho".