Karl was mentioning how the pie charts help him balance his training since he does SBR. Since I only do B, I was a little disapointed this didn't help me. Then I thought, why not, I do hills, intervals, group rides, etc.. I'd love to see my cycling broken up with sub-types.
Then as I'm writing this, when we can enter user defined activities, I think I get this for free, I just do cycling-hills, cycling-intervals, etc..