That’s not true. People’s principles go out the window at the promise of easy quick cash.
Unless I'm also misunderstanding, to reap the benefit of a crypto-currency you'd in most cases have to at some point transfer back to standard currencies.
The success of the currency is measured against the USD or GBP etc, and to use in the real world would mean accepting a standard equivalent.
I don't have an issue with trading digital-currencies as for me they're more akin to a decentralised share system (ownership of an asset) rather than a currency.
It's a long way off being an actual independent currency in its own right. My friend, who does well from crypto, agrees with much of the above.