Of course this changes, but that's how it is now, #1
and same as all other cryptonight coin it can be mined by GPU but without big advantage, please google about specifics of cryptonight and you will learn that GPUs don't have such huge advantage as for example when mining bitcoin or ethereum.
Check this page for example https://en.bitcoin.it/wiki/CryptoNight to understand how it works.
GPUs don't have a huge advantage?
You mean you can cram 12 CPUs on a single board?
Even if you find a way to do it, how much power draw will they have?
How much space they are going to take? How noisy?
You can just go in any computer shop and buy these CPUs and a single motherboard?
I would agree that: CPU mining Cryptonight is also profitable, but GPUs will always have advantage.