The interesting part is state transitions (mutations). How would your Apache server coordinate mutations to your cat database with other servers when you need to enforce invariants like the maximum number of kittens a cat can have per year?
I'm hosting cat photos for friends to view. There are no invariants. There are no rules. It's purely content I'm posting for other people to consume. It's no different than if I printed photos and mailed them to all the people.
Every financial transaction that requires settlement between institutions is a “coordinated mutation.”
And while it is true that financial transactions are often synced between institutions via a “batched mutation” approach (especially when coordinating settlement), the delay that batched settlement represents, and the complexity that it introduces to the overall system, is extremely costly.
This is one reason why blockchains have the potential to be extremely valuable—both from a utilitarian point of view as well as from a financial point of view.
Imagine if you could get rid of batched settlement between institutions, because you just didn’t need to do it anymore. What would that be worth?
Bitcoin transactions can take anywhere from 10 minutes to upwards of 16 hours for minuscule volumes of transactions. It's not solving that problem for certain.
> extremely costly
The cost is built into the transactions. Just like it is with blockchain transactions. Now then, which has higher per transaction costs?
As a factual matter, settlement costs are not fully embodied by transaction fees, and include such things as, for instance, financing and opportunity costs and the cost of supporting an organization that is more complex than it otherwise needs to be. If settlement delays were entirely eliminated, new business models would emerge that are not even possible under the current regime.