As a normal individual contributor not at the C-level or even management level, I just assume the value of any options/shares I receive is zero unless an accountant or the IRS tells me I should believe otherwise. Too many goofy fine-print shenanigans like this to keep track of.
You can't possibly actually values your shares at zero. Test: can I have all of your shares? No? Well then you must value them at _something_. What if I gave you $1? 10? $100? Just because something is (even incredibly) risky doesn't mean its value is zero.
Most private equity is worthless in a couple of years. Most companies crash before any liquidity event. Those that don reach an event, have such a preference stack, and so for such a pittance, the options are underwater.
It’s a mindset.