If you truthfully believe bitcoin will develop into a stable alternative to state run currencies, great, I wish you good luck.
I don’t. To me it is like religion - they can’t all be right and they are mutually exclusive. I don’t trust myself to be able to pick the winner among all the losers.
The answer surely can't be "every currency issued by a government is stable forever and every crypto-currency will collapse before 5 years".
What I'm saying is, there are a lot of currencies out there, and some are more stable and have a better track record than others. You may not trust yourself to pick a winner among the losers, but I suspect you do use at least one currency from time to time, so you have picked one by default.