Say a development team includes (or makes use of) graphic artists who create all the images that go into a product. Such things include icons, bitmaps, window backgrounds,
With respect to diff and merging, I think the version control is more critical for graphics and media elements. If you think about it, most designers are going to be the sole owners of a file -- at least in the case of graphics -- or at least I would think that'd be the case. I'd be curious to hear from a designer.