I am sure the monitor could be set up to work as a plain (m)DP monitor even if it had a built-in graphic card, bypassing it should not be rocket science. It thus would not be Mac-only.The design problems with moving some "hardcore" GPU to the monitor is that it increase costs. If you try to push the limits it increases heat. It also makes the monitor useless with conventional graphics cards. ( it will only work with Macs.
But the additional cost naturally remains.