Currently, when you create a new template in the site editor it is published immediately, but there is no feedback to confirm this except for the disabled Save button which isn't particularly clear :)

This may be something to address in the mean time, but more importantly let's discuss whether templates should be published instantly like this, or require an additional user action.

A strong argument against auto-publishing is that the user may not understand the frontend of their site is affected immediately after creating the template. In the example video above I may leisurely go about creating my tag template over an extended period of time without realising that tag archives on the frontend could be broken until I'm done.

cc @WordPress/gutenberg-design