Ah yes Bitcoin, famously free of fraud and abuse.

More seriously, every system can be used for fraud. The question is whether the solution is actually better overall. We could prevent all wire fraud by returning to a cash-only economy. But that would be hugely inconvenient and therefore create a huge drag on the economy compared to a world where we can do electronic transfers even though electronic transfers open us up to wire fraud. Returning to cash-only is not worth the increase in security, and it opens us up to other issues (e.g., bank runs and someone stealing all the money under my mattress).

And while power use is a problem with Proof of Work coins, it's not my biggest concern about cryptocurrency because Proof of Stake can fix that issue. It's a shame that the biggest coin now is PoW but hopefully that will change. The bigger issue is "is cryptocurrency better than traditional currency?" So far it hasn't proven to be better except in extremely limited circumstances. And a lot of the ways cryptocurrency is better will go away if governments start regulating it like other forms of finance. Having your money in cryptocurrency won't protect you from the police and courts.

We trusted bankers to invest our money, and some short sold the housing market with that money

Okay? You could do that with cryptocurrency if traders started accepting cryptocurrency for shorts. The only reason you can't do that today is traders won't accept cryptocurrency for shorts, and that's basically security through obscurity.