Why destroy all his assets?

I get the whole thing about you have to have nothing and not care about anything to be a tough guy, but really why destroy everything? The heists he pulled off were so technically challenging that breaking into that boss guy's house and blowing him away was child's play in comparison. And if he does succeed, he's needlessly lost everything. Also what was the point of not explaining anything to his wife? Why not just tell her some crime boss will kill her and the baby unless they go into hiding, explain he has to take the boss out and that if he makes it he will find them later.

I think the problem is they rushed the ending. Killing the boss was so quick and easy that Frank's big mental prep of destroying everything he owned seemed senseless and unnecessary. The movie should have been a half an hour longer I think, showing Frank casing the boss, the boss's reaction when he finds out Frank destroyed everything, maybe Frank being captured and tortured. It needed something to make his actions seem necessary.

Or did I miss something?