A lot of people who are familiar with both player would choose to build their team over Kopitar. There is so much more to hockey than just putting up points.
Kopitar has 4x the hits, 3x the blocked shots, takes faceoffs, put up almost identical PP points, plays more minutes, plays the PK, better +/-, and took less time off from injury. Is that worth the .1ppg difference between players over the course of their careers? Probably not when you factor in Kopitar is currently pacing .1ppg better than Kane over the past 3 seasons.
A fun fact for Kane is that he's never scored a SHG. The guy hasn't averaged more than 2 seconds of PK time per game for the past 7 seasons, or more than 4 seconds of PK time per game in the past 16 seasons. He has 6 seasons where he averaged 0 seconds per game.
I have no issue with people choosing Kane as peak and prime. But I think Kopitar has been underrated his entire career.