However effectively the Brexit vote is an expression of sovereignty of the populace. It's about power. Why? Because some parliament members are afraid to oppose the outcome.

Of course some things are different from the Swiss direct democracy. First the votes aren't ordained by politicians as a gamble but are set in motion by predefined rules in constitution and law. Second, the federal minister (Bundesrat) who has «lost» a vote doesn't retire like Mr. Cameron. Quite the opposite: everybody expects that he obeys the people and takes over to try to find the best way. Like a child who has to obey its parents and can't retire if he disagrees.