I think it's important that Amazon provides stuff like this in the stock UI. Sure, a 3rd party like TV or whatever might have been able to do something similar, but they only have reviews from turkers to go off of. Turkers aren't always the most reliable when it comes to reporting approval times, rejections, etc. This data comes straight from MTurk, so it's at least accurate.
It also cuts down on the need for 3rd party tools, which I think is a good thing. It may not seem like much to those of us that have been around and know our way on MTurk, but I think it can be really beneficial to newer turkers coming in. I see so many people starting up on MTurk, not really knowing what sort of tools they should be using or even knowing what scripts are, and they end up getting burned by requesters with bad reputations because they don't know any better. Hopefully, this can cut down on that a bit.
However, I do feel like that data needs to show a shorter time-frame than two years. Just because a requester posted a million HITs a year and a half ago and approved them all doesn't mean that they couldn't have gone reject-crazy in their more recent batches. That data would do a pretty poor job at reflecting that.