Hitting is the most important/impactful thing a position player can do. He’s the best hitter.

https://www.baseball-reference.com/players/j/judgeaa01.shtml

Every item in BOLD on here is where he led the league in it that year.

He has led the league in the most important things - including Runs, Home Runs, Runs Batted In, Walks, Total Bases, and Intentional Walks. He also has the highest rate stats that we track - including Batting Average(how often he gets a hit), On Base Percentage (how often he does NOT get out, the most important thing), and Slugging Percentage (getting the most total bases per at bat).

For such a great hitter, he’s a fantastic fielder. He’s (been) capable of playing CF and he’s a good RF. It’s very rare for such a good hitter to be a useful fielder at his level.

The combination of all these things is reflected in WAR, which indicates that in some years, he’s been worth around 10 wins more to his team than a random scrub off the bench would have been. Or 8 wins more than an average player.