This is pretty common practice in the film industry because of resolution on screen, its because the textures need to be sharp, even a 4k texture on 1 tile wont stand up alot of the time on screen, so models have to have their uvs spread and made bigger and the best way is to tile it like this. I can safely tell you that we are using 25+ tiles for some models. It can be a nightmare putting the uv layout together, and on top of that they all have to share the same ratio.

cheers
Jay