You can make money off of any commodity volatility. I heard stories as a boy of guys who horded rubber tires and sold them at prices way above their worth during the Second World War. There was a scarcity of raw rubber, Japan had occupied the rubber producing countries in Asia. Neoprene (synthetic) rubber was not invented yet.
But rubber tires did have utility -- they were a useful commodity in trade.
Digital currency is 'air' it has little if any utility. If you can make money off of speculation -- that's fine --but don't cry if you get burned.
You either converted mining 'air' and electricity expended into a new form of air;or,
If you purchase digital 'currency' assets with hard asset national currency -- you are buying air with real cash -- keep that in mind.
Good luck to the winners ...