Normally, the main point of money is to exchange it for goods. But you can't securely and trustlessly exchange bitcoin for goods, since goods are not on-chain. So all the fancy cryptography is not solving the main problem that it would have been useful to solve.
I believe the parent was elaborating on their point here:
> it's impossible to do anything with it except moving it from one account to another without requiring trust of the other party.
Goods may need to be shipped, they could be counterfeit, etc. Bitcoin provides no facility for escrow or refunds - just moving tokens from one wallet to another. So you need to trust your counter party even more than you would with e.g. a credit card in order to transact.
Also, you can mine fresh bitcoin without trusting another party.