Indeed the right to buy a stock is valuable, but as an employee / the state you should postpone the taxation to when the value is actually retrieved by the pers

Indeed the right to buy a stock is valuable, but as an employee / the state you should postpone the taxation to when the value is actually retrieved by the person you tax. It's a bit like saying 'You're house is worth X, you should be taxed regarding this price, even if you don't have yet made any profit'