He can play it, and is getting better with experience. He has also said that he likes playing CF, which is half the battle (see results of Reyes trying to play 3B)
With both Bruce and Granderson probably not returning next season, Conforto would be fine in CF, or I'd also have no problem with him playing RF with Nimmo in CF. Actually it would be a toss up between those 2 as far as who plays CF vs RF.
If they do bring Bruce back in RF, Conforto in CF with Nimmo and Lagares as the 4th and 5th OF would make a solid outfield.