At first, the idea of Apple including a GPU in the external display may sound crazy. Our sources explain that the reason for it is primarily for compatibility with as many future Macs as possible. Due to the immense graphics needs required to push 5K worth of pixels, normal super high-resolution displays require connected computers to include significantly powerful GPUs.
If the GPU is used only to push the display’s pixels, and not add any more ‘oomph’ to a connected Mac, then I can see this happening.
I will however consider this a lost opportunity. The ability to use a regular MacBook 12″ for Final Cut Pro X, gaming, etc. would be too good to pass up for me personally.