My guess would be to make sure theres no bleeding and such after the surgery. Maybe also for hormone replacement therapy. I see Rx's all the time from OB/GYN's for hormone replacement therapy...a regular MD might work as well, not for sure.
Because you could still develop cancer, etc... particularly if you're sexually active :-)
if your hysterectomy was due to cancer, you still need 1 to make sure they got all the cells, and even if it wasnt due to cancer, most doctors still do rectal exams, breast exams, blood work,blood pressure, check your bladder and so forth. however it is very rare, it is possible for vaginal cancer to develop.i would rather be safe, than sorry. some doctors say you dont need one, and some doctors insist on having them done. i'm glad my doctor insists, you just never know these days