But as the stock vests, isnt that treated as income and taxed anyway? And then taxed again if I sell (as capital gains)?
If so then it comes down to a gamble of whether the stock is going to go up by the time the stock vests and whether you happen to have the spare cash around to pay a tax bill.
Am i reading that right?
The other thing to consider is your vesting timeline. As you vest, you'll owe additional taxes, which means a sizable tax bill before there's been a liquidity event. If you are rich enough to afford that then hey, go for it. But not everyone is in a position to be able to do that.
You need an 83b if you think the stock will vest before you can sell it. Imagine having $10M of stock vest, no option to sell it, and no way to pay the tax on it.
It is a weird artifact of the way vesting triggers taxation of unrealized gains and it fucks people all the time.