The big issue is it's hard to test the actual problem solving process in math with a multiple choice exam so you're either stuck doing it in higher level classes with less people so you're not drowning in grading or clearing/removing calculators entirely. The option of just not having calculators and formulating the problems so they could be solved without them was the most common solution to that when I was in college. Usually it's relatively easy to select a set of parameters for the problem to make the solution easy to compute numerically.
I'm in the UK and there was nearly no multiple choice exams, both external and internal. Most external exams used scanning software with questions split out to make it faster to mark them. Somehow our teachers managed.
The only multiple choice exams were optional additions the school could purchase, ie: Maths Challenge, benchmarking, career advice...
In the US basically every large exam especially the end of year and college admissions tests (except the essay portion recently added to the SAT when I took it) were all bubble forms. In college it was most common in the large classes that were part of the options for the general education requirements that would use them instead of open ended questions so they could be automatically graded for the 50-100 students who'd be taking each exam. It was also way more common in classes where answers would be numerical rather than say my proofs and logic class where we needed to write out a proof. IMO it was deployed logically where multiple choice made sense it was used and classes where the path to the solution was important they'd not use it.
