The scheme to arrest the Bank of Greece governor & raiding national mint was separate to the Varoufakis' plan, and to try to combine the two is a huge mistake. That plan was just dumb, while the Varoufakis plan was crazy and or subtle.
I view Varoufakis's plan as a trump card to play against the Troika. The Troika believe that - in the end - the Greeks would always roll over and give in to their proposals.
Varoufakis plan was to be able to say "you didn't count on this crazy plan* and be able to present something that was undoubtedly crazy, but just credible enough to make the Troika think that the Greeks might try it.
Sometimes acting crazy is the best strategy. To quote:
it turns out that the best strategy if you get to play the game only once is to make the most credible attempt possible in pretending to be a Hawk while actually being a Dove. When you are in one of the cars heading for each other, growl, scream, throw bottles out he window, swerve and then come back onto the road again. In short give the impression that you are mad and unpredictable, and definitely capable of doing mad things like not swerving under any circumstances. Do not signal that you may compromise, even though you know you will.
[1] http://karlstrobl.com/2015/05/28/varoufakis-and-game-theory/