It is how most databases, filesystems and distributed systems work, so we know how to build those things, we don't even need merkle trees. And despite the fact

It is how most databases, filesystems and distributed systems work, so we know how to build those things, we don't even need merkle trees. And despite the fact that many real world problems can be better modeled with an append only log and a derived state, somehow 99% of software systems opt to store the derived state only.