I can already spend Bitcoin in order to legally avoid paying taxes, and I'm definitely not the only one. It's not for nothing that quite some rich coiners have bought properties and whatnot directly with Bitcoin.

The only thing is that when too many people start doing this to avoid taxation, and the government starts to notice that, they might change their mind and even tax Bitcoins that you spend.

Governments don't care about people, they just want to make sure their income doesn't suffer a blow because of how people are trying to use the law against the government in a legal manner. Enjoy while we still can spend without taxation.