Options have different tax implications than stock.
So for instance, an employee that gets a big pile of options in an illiquid stock doesn't necessarily experience a taxable event. This is good for the employee.
If the stock later becomes liquid and worth a lot, the employee can exercise the options and cover any taxes by selling the resulting stock.
however if you buy them while they are still valued at the option price you also don't experience a taxable event .... and you can lock in the purchase as a potential capital gain (and possibly pay lower tax when you do sell them) ... the down side is you've invested in something you probably can't get back until when (and if) it goes public.
So the time I was a founder and got 100k options at 1c I bought the stock and started the capital gains clock ticking (but then lost the $1k when things crashed and burned). But when I got 10000 options at $1, I didn't buy them for $10k, but made $250k when the company went public -but paid tax at my marginal rate (43% in CA).
You have to make choices depending on your circumstances and tolerance for risk
So for instance, an employee that gets a big pile of options in an illiquid stock doesn't necessarily experience a taxable event. This is good for the employee.
If the stock later becomes liquid and worth a lot, the employee can exercise the options and cover any taxes by selling the resulting stock.