The problem with that is, these transactions are now on an immutable ledger (which is the actual use case of block chains).
These transactions could have been made with any "thing" that enough people agree has some value.
"any" is going a lot of heavy lifting there.
Apart from people agreeing on value, that thing also has to be: 1. out of their governments' control (all the examples had governments gone bad), 2. easy to transfer/carry, 3. durable.
Can you please name a few alternatives if you think that's a simple problem?
Bitcoin fits the bill for those aspects. Can you name a few other "things"?
I do not disagree that blockchain tech has a good use case. It's just that it does one thing: a distributed ledger. That's it.