Some of the larger wikis have issues with images from Commons being used on highly visible pages, as it creates the possibility of vandalism happening on unprotected Commons images. The general workaround has been to upload copies of the images locally, usually using a bot, which is hackish and needs a better implementation.
With the implementation of GlobalUsage, it should be possible to create a local upload blacklist at Commons, similar to the bad image list or spam blacklist. This upload blacklist would be in a format like:
- enwiki|Main Page
When a non-admin tries to upload an image on Commons that matches by title and wiki to a globalimagelinks entry and that matches to an entry at this Commons upload blacklist, the upload would be disallowed for non-admins.
Assuming that the globalimagelinks table updates quickly enough, this should make the current bots and manual updates unnecessary.