It's more than just a place to work on cars- they have stuff like mills, lathes, even roto-blowing machines for plastics!
I think this place exists where it does in part because land is so expensive in that area that not many people can afford to devote space at home for such stuff, and also that half of the readership of Make magazine probably live in that area (i'm guessing about that last statistic, but I bet there are lots of people there like me that find the non-automotive stuff just as interesting as the lift, the welders, etc).
My guess is that they are expecting more non-auto uses, based on the number and quantity of the tools they have or plan to have. If I owned such a shop, that's probably what I'd stress as well, since one guy in a 64 Chevy Lowrider will consume the same amount of space as 4 people machining parts for their kit car, their robots, a broken gate, etc. That greater density means greater revenue and better machine utilization in the same amount of space. The risks of non-auto uses are probably also lower as a piece of steel being polished on a lathe typically isn't at risk of erupting into fire (as might happen when people get a torch and decide to just cut that stuck tailpipe off).
The company structure seems to be an LLC, so that gives as much protection to the owners and investors as can reasonably be expected.
If they are the least bit clever, they will see other ways to make money, including stocking raw materials, consumables for the equipment, more billable classes, a "platinum circle" for members that offers more benefits, hosted competitions for robot fights where the machines had to have been substantially made at the shop, offering skilled labor at an hourly rate when a person who is good at welding but needs machining help just needs a part done quickly, fee-based storage of cars, parts, projects, etc. The possibilities are endless for an engaged marketer.
I wish they'd open one here in the DC area. I'd sign up.
-Will