From my own experience this is _exactly_ what happens. Only they intelligently manipulated my shareholder agreement in a way that I had to actually buy the options, no paper transfer, I needed cold, hard cash. Having very little money at the time (being between jobs) I was unable to do so, which meant that I forfeited my options. Probably for the best anyway, because buying them didn't guarantee a buyout, only the option of one. I would have been out $5000, just waiting for the day to be bought out, which would probably never come.
Lesson learned: read things very carefully, confusing language is intended to be confusing. I basically gave away two years of my career to kool-aid equity. Just be really careful, and if you don't fully understand something ask someone who does understand. If you can't get a direct answer, leave. Don't waist your time; you're being gamed.
There is no real gain in convenience compared to a Starbucks Card or cash, and you still have a paper receipt involved in the transaction. I'm having a hard time seeing how this is a step forward.
Strip employees of all decision making and reasoning because that stuff is expensive. Create a protocol that they must follow, how could it possibly fail?