I was actually thinking about writing a post about this myself, in my opinion it's a mistake to compare cryptocurrencies to commodities and fiat currencies. I personally think the bubbles and eventual bursting of bubbles in fiat currency systems stem from dishonesty in regards to true value because value of these currencies can be manipulated pretty much at will by governments. Cryptocurrencies are transparent by nature which combined with the fact they're decentralised basically means that you can't actually lend money you don't have (basically the cause of every bubble).