Libraries offer two permission settings - "View and use" and “Edit.” In order for creatives to use the contents of a library - drag and drop graphics, apply colors, fonts, character styles, etc - they must have at least “View” permission. This permission gives slightly more access than a traditional “View” in that they can also use the library.
Users with "Edit" permission can do more advanced library management - edit the library contents (delete, rename, add), create and modify groups in the library, share the library with other users, and even delete the entire library.
In the case of a corporate style guide, the small number of members of your brand team should be configured as editors, and all other library collaborators can be granted just “View” permission.