We had micro labs that used microscopes (about 7 sessions), but that was it.
In terms of practicing physicians, it depends on a lot on your specialty and your hospital. On medicine so far, I haven't seen anyone use microscopes at my academic institution and large hospital. And I can't think of a reason for cardio to use one but maybe there is one. However, I saw them used quite frequently in inpatient OB and clinic. I'm sure Heme people know how to do blood smears. So it is possible to use microscopes as a physician, but I don't think it's very common. Maybe smaller hospitals with smaller lab capabilities would have more opportunities.