Expected value is not $millions. Expected value is a few hundred $k (usually, if you are realistic about the potential of the business and your tiny share as an employee) MULTIPLIED by the relatively small chance of hitting that exit, say 1%. In short, a few thousand dollars, which is approximately what you get by multiplying out the strike price.
IMHO it takes risk into account in a very sobering way.
But just looking at expected value ignores risk. Most people are risk averse, especially at the amounts of money we're talking about here.