The name is a description of how the studio works, not a flourish. G is George Jillard, who founded the studio and leads every project. &Co is the collective: a group of specialist designers, writers, developers and photographers assembled around each brief rather than carried as overhead.
It means the client gets senior people throughout, and the team on a travel rebrand looks different to the team on a product interface, which is how it should be and almost never is.