Versioning templates would allow for better template management across environments where the Zabbix DB is not the master source of templates.
While the Zabbix GUI is ideal for modifying templates, it's not good for maintaining control of them through change management/versioning practices.

Ideally, each update to the template would automatically increment the version. Exports would contain the version number.

This would allow us to determine whether an exported template is higher or lower version than that on the server.

For deployment automation, it allows us to intelligently decide whether to import (and overwrite) a template or not.
At present, I'm using the exports as the "master source", but I always have to overwrite - which when done via the API is quite slow. Using versioning to only import those of a higher version would speed this process up considerably.

Using template exports seems to be the best way to manage Zabbix Templates via Ansible/Puppet/etc., since its the only native method for exporting template data.