"My main message to pass on is that if/when we are coralled into accepting government/corporate centralised digital currency, we are then very vulnerable to being trapped come any future financial crash"
Currency is tied to the taxational ability of nation states. So-called "Cryptocurrencies" are hypothetical units in electronic ledgers whose value is the result of being traded as commodities. If you can't pay government dues in it, then its not currency: and as you can't, therefore it isn't.