It is not possible to display Scaffolding's live-template macro to users who don't have access to the Space.
Unless the template is setup as a Global template.
As a user I have access to Space A and Space B, I can use the template created in Space A on Space B. However, users who don't have access to Space A are unable to view the template due to permission restriction.
I would like to request that even with Space restriction, the template is still visible.
Our decision is not to proceed. Introducing this feature would violate the permission architecture in Confluence.
It is recommended that the template is hosted in the same space, or in a dedicated space that hosts all the templates and accessible by everyone.