"Treat as zero" is bad advice. "Treat as 10x or 50x cheaper than they say it is" - that's good advice. The difference is that 10x more equity solves a lot of problems with equity, and it's not what you'll be gunning for if you think its value is zero.
Right, because it's better to be paid $X/year and have 0 stock options than it is to be paid $X/year and have Y stock options, and no sane person would prefer the latter or negotiate for a Y large enough to be worth something even if the startup doesn't "make it" but is sold for 5x less than they tell you the IPO is going to be. And a company that has already got $200M invested into it is just as likely to fail to grow in value as a 1-person startup operating from a dorm room - it's always a 1 in a million lottery ticket. Only after IPO do RSUs suddenly gain value from 0 to something.
Given loss aversion and human talent for rationalising their sunk cost, do you really think you'll be able to accurately value those options? Treating them as worth 0/ε is a good heuristic, it'll give you the right decision basically every time.
