I also really like this feature. I find myself looking at the historical crowd levels a lot.
According to touring plans website they predicted a crowd level of 3 for MK on the 11th, but crowds observed were actually a 1. It's worth noting that they only use certain attractions in their algorithm. In MK, these are BTMRR, Buzz, JC, PP, PotC, SM, Splash, and WtP.