Although I keep all my savings in fiat at the moment, I can still understand the value of crypto, and the position of libertarians.
Should the government have the power to seize all your assets and savings?
Some will say yes, because they believe the government will always be just. Others don't trust the government to always do the right thing, and so believe it shouldn't have those powers to begin with. This is an especially common belief among the technically apt crowd, who watched whistleblowers like Snowden be punished for exposing mass surveillance. That eroded a lot of trust in the institutions of the United States. Citizens of other states may have even less trust in their institutions.
Some don't agree with what they consider to be reckless and needless levels of spending - especially when that money is wasted by a public sector that tends to be inefficient, corrupt, bureaucratic, and incompetent - that will have to be repaid through either perpetually increasing taxes or inflation. Even Alan Greenspan recently cited inflation as his top concern. Again, the situation is probably much worse in many other countries, where politicians pilfer public coffers, assign contracts to friends, or generally poorly allocate your money (whether through taxes or inflation).
If you believe the government cannot be tyrannical, aren't bothered by high taxes or inflation, aren't concerned by waste or corruption, then I could understand why you don't see the value of a currency outside of the jurisdiction of your government.
Of course, there are downsides as well, like facilitating criminal activity that does hurt regular people, or facilitating tax evasion for necessary spending and services. That can't be ignored either.
And of course governments are going to do everything they can to stop this- what makes it interesting is the wide-spread effort to make it generally difficult to do so.