The valuation has the "implicit" success baked into the price already-- and I don't think you could say Uber is a guaranteed success story yet. With CK, you take the risk of being an early employee with very little, if any, upside. This came up in other threads recently, but it's likely better odds to stick with Big N companies.

One angle people might be missing is how much CK is a real estate play. There's real technical problems to tackle, but it requires spinning up these dark kitchens in dense, pricy real estate markets. Conceptually, it's the WeWork of restaurant kitchens, though I'm hesitant to draw that comparison due to the many other connotations of WeWork that I wouldn't associate with CK.