In a screen network, branding is the problem of staying consistent across places nobody from head office is standing in. The design work is the easy half; the hard half is that a hundred screens, some portrait, some in bright sun, some updated by a store manager on a Tuesday, will drift apart unless the system prevents it.
What prevents it is structural rather than aesthetic: locked templates with editable regions, an asset library that is the only source of logos, and publishing permissions that let local staff change a price but not the layout. Brand guidelines in a PDF do not survive contact with a busy store.
The caveat is that over-locking is the opposite failure and just as common. If a store cannot post its own opening-hours notice without a head-office request, they will print one and tape it to the screen, which is worse for the brand than the layout they would have produced. The controls have to leave a legitimate path for local content.
Judge a template system by what a non-designer can change without breaking anything, not by how much it forbids.