I have been hunting with a 20 gauge since 2017. Mine is a compact 870 that has inserts in the butt pad to increase the LOP. I am 6'1", and it fits me just fine. So why the switch? Mine is two fold. One is the size and weight difference when climbing steep hills trying to get the right setup on a gobbling bird. The maneuverability of the 21" barrel and the weight is super nice. The second reason is reduced recoil. I had back surgery in 2017 and a blown out disc in my neck in 2019. Call me what you want, but I don't want to think about shooting a 3.5" 12 ga anymore because I don't have to. In 2019, I even loaded my 20 ga shells with a reduced payload to reduce recoil even more as the doctor really didn't want me to be shooting a gun at all.
So what am I giving up by doing this? Nothing in my opinion..........my current setup shoots a pattern at 40 yds just as good or better as my 3.5" 12 ga shooting #6 longbeards.
I say to each their own and really doesn't matter what others think. I am not trying to impress anyone. I just like the the size, weight, and recoil reduction without giving up anything. It will kill a turkey a lot farther than I should be shooting at one.