My guess is so that no one would get pissed off at the rules that come with the stock grant and use the extra comp to get an equivalent per-year salary from som

My guess is so that no one would get pissed off at the rules that come with the stock grant and use the extra comp to get an equivalent per-year salary from someone else. If you get a million dollar stock grant that vests over 8 years, that's $125,000 in stock per year. Startups don't usually pay super well, so I wouldn't be surprised if you could get something equivalent from Google or Facebook. Especially if you come in with the stock grant paperwork, effectively making that your current compensation. You could maybe even get a raise. They only have 140 employees; if 10 get pissed off an leave, that's 7% turnover right before their IPO, which is bad. This will still likely lock a lot of their employees in, without the risk of them quitting right before the IPO.