What are you talking about? The dollar loses to inflation every year. A 1990 dollar is $1.87 in 2017 dollars.
That said this is only true if you have faith in your government.
Obviously cryptocurrencies are sharp tools, but they're stronger financial primitives than what we have. We just need to use them to rebuild the consumer-facing components.
It is a 3000 year old problem.
Trust. In short, is big business.
If given the choice between the whims of banks vs the whims of cryptocurrency speculators, and the potential for wire-fraud vs the potential for wholesale 'hackfraud', I think I'll take the whims of the banks please.
Regarding bank whims, if you're a properly banked person who's never had an issue, great. If you've never had trouble with the IRS or anyone else who can take your money by force- great. But that's not everyone.
https://en.wikipedia.org/wiki/Nixon_shock
to give just 1 example.
Having hard limits on what governments can do is obviously beneficial especially for less informed people.
EDIT: misread! Obviously ETH lost a lot of value.
Which is precisely why you don't leave money sitting in a 0% savings account. You invest it in equity, not a currency. Fiat is designed to lose value through inflation. Thats how the system works.
Expecting to hedge against inflation by dumping your money in another currency is insanity. The only way is through actual economic growth.
Bitcoin has been a great hedge for those who can access it in Venezuela.