Paying members of Project-GC have the option of including Lab Caches in your stats. Its under 'Settings', near the top of your 'Profile Stats' page. This does not include the data in checkers however.....
The rest of this answer skips any discussion about if Lab Caches are real caches or not.....which is obviously a real and live topic......
Lab caches have long been problematic for the challenge checkers.... Lab caches simply do not have most of the data that the checkers rely on.
A Lab Cache does not have difficulty or terrain, no coordinates, no Country, Region or County, does not have an owner, no size, no elevation, no favorite points.... and so on. These are what most checkers are built to check.
You are correct that some challenges, like streaks, would work fine with Lab's included by default, but a lot of old checkers (that pre-date Labs) would simply break if Lab cache data was returned to them.
