It practically eliminates the opportunity-cost of leaving. Having seven years to be able to come up with the liquidity to pay the strike/taxes -- plus, critically, being able to wait several years to get a better understanding of whether the options have value before striking -- completely changes the calculus of whether to depart a company, whether because you're unhappy or because you've found something better elsewhere.

Agree this is good for Uber employees and I'm happy they have significantly less of an impediment to leaving than most other workers at pre-exit startups.