Pogba is very talented. You can pretty much throw him anywhere on the pitch and you'll get a result out of him. Unfortunately, our wing backs leave a lot to be desired and Pogba can probably cause more damage on the songs that someone like padoin or isla, but against very good teams, he will be a liability on the wing. In that position, you basically need two necessary attributes before you can even begin to be considered, you need to have speed and a very high work rate. If asamoah was more talented in attack, if he had better crosses and passes, he would be the perfect winger. Pogba, on the other hand, isn't fast, and doesn't have a very high Work rate. It's not about being young aor old, it's just the way his body is built.
I personally think we can get the best out of him if he played in a more central position. It fits his talents a lot more. However, in games against teams that park the bus, including him would not be a bag idea. We wouldn't really need him to run that much, just be productive in attack. bit I would be very very very surprised if conte tries him in that position against a team like Madrid