The way I think of it (and I've said this before) is that you can either:
1) Make your own judgments, use the "eye test", etc. This is EXTREMELY limited. How many games did I honestly watch of these two players this year? I'm a Yankees fan. I watch almost every single Yankees game. With that being said, I don't watch Miguel Cabrera or Mike Trout on a regular basis. So how can my "eye test" be accurate? Even if I did watch every single game, since when is "eye test" accurate? Even MLB scouts don't get everything right.
or
2) Base your judgments off of statistics that have been endlessly researched from REAL game situations. Are these perfect? No. Are they more accurate than someone judging based on things like the Triple Crown? Yes. That is laughable.