Distributing and managing Postgres SCHEMAs with an EXTENSION?
It may make sense to distribute to third party PG users as EXTENSIONS, but it doesn't make sense to bundle their data as EXTENSIONS.


it's more work,
it won't be backed up by pg_dump


Because it won't be backed up by pg_dump, you'll have to add to your development repository their data rather than just the initial load scripts. For the added complexity of backing things up, it doesn't seem advisable to do this.