When people say a player is a pp specialist, they generally mean that the player is great on the powerplay, but doesn't provide much at even strength.
Since entering the NHL, Caufield has scored 81 goals and 149 pts.
Only 21 of those goals and 44 of those pts were on the pp.
His production coming from the pp is a lesser % than many star players in the nhl.
When I say that he can be used on the 2nd line and the numerical advantage it is to give him playing time. With more playing time at 5 vs 4 and less at 5 vs 5, he will score more at 5 vs 4 and less at 5 vs 5. Especially if he doesn't play on the 1st line next to the two best on the team.
Small guys like Caufield and Hutson must be prioritized over numerical advantages. There are just as many shorthanded minutes, and these minutes must be taken by those who are the best defenders. Slafkovsky, Suzuki, Dach must be able to play these minutes as fresh as possible.
12 minutes at 5 vs 5 against weaker lines, 3 minutes at 5 vs 4, Caufield will be more effective in his qualities and less handicapping in his weaknesses.