In terms of liquidity and it being "a sure thing", an acquihire would surely be better for Exec. But Justin Kan already has a few successful endeavors under his belt and probably isn't hurting for a quick check. Increasing his odds for a homerun probably makes more sense. The same probably goes for the investors.

For the employees on the other hand, an acquihire and subsequent retention package would most likely have a better EV/Risk ratio.