I 100% agree with the idea that nobody should ever use the Bitcoin blockchain for anything other than financial transactions. There is plenty of space given the 100 bytes of the Coinbase and 83 bytes of the OP_RETURN to reference anything that anyone wants to do off chain.
That said, I also have a problem with the idea that anyone can come along and change that 'should' into a 'thou shalt' or 'thou shalt not'. Just because I believe something doesn't mean that I have the authority to demand and enforce anyone else to believe the same thing. People coming along claiming that they have that authority are usually people that I don't want to deal with very much. The entire concept of Bitcoin is built with the voluntary nature of the system at the forefront. Being able to do something is paramount, being denied the ability to do something is not.
Bitcoin provides the natural economic incentive layer that makes it the best way to conduct financial transactions in exchange for goods and services in the spatial world, or content in the metaverse. Those who can see the advantages are using it, those who cannot yet see it are not using it. What we need is an economic incentive layer for using Bitcoin transactions as a time stamp on the immutable blockchain, referencing content off chain. If that incentive is strong enough, all of the other options fall away as the opportunity cost reveals itself.
Financial transactions on an immutable provenance record is the first corner of the foundation of a wealth based civilization. But it's only one corner. Let's build the rest.
