Sebbbi's talked about it having a lot of uses on b3d. Iirc, he also said INT16 can replace INT32 in many cases.
I looked up on some of his posts. Turns out that indeed, according to him, many post process are done with normalized vectors that falls into the [-1,1] range and for that fp16 would be suited.
He also mentions that it could be used for a LDR pass (some HDR implementations like Halo 3 mix a LDR and a MDR pass for delivering a HDR image).
For spatial math it's no good, unless you use many local coordinates to always work very locally to the coordinate center...
So I'm changing my tone, fp16 is not completely useless. There's indeed some cases were it could be applicable, though I still wonder it's worth the trouble, because mixing fp16 and fp32 math seems really boring to get everything right, specially if you don't know exactly the magnitude of every variable... Specially when in the aforementioned use cases are more bandwidth bound than math anyway (though there are some bandwidth savings to be made as well).
I think if fp16 has indeed any merit we will see it first on mobile, they will probably push it there as alu time and bandwidth matters a lot due battery life concerns, and from there make into console and pc space.
I see a larger trend for regressing to FP16, not just for post. Like that dreadful racing game on the PS4 Pro. HDR/ 10-12bit color is going to make FP16 post insufficient anyway.
Does that game actually use any fp16 shader or it was just speculation on DF part?
I honestly see no reason as to why they would have to resort to it, it's a very simple looking game, with very simple shaders, that a regular ps4 would have no trouble going over 1080p, and they even dropped the AA when running 4k on pro.
It's time to wake up, FP16 is not useless a lot of you are just stuck in your ways & don't want to accept that things are not as you thought.
In the very least it has a very limited usability due the incredible low precision. Fp16/int16 has an okay range if that's what the problem needs, but very low precision. Really, for any number that doesn't start with 0.something.
But, there's indeed some uses that doesn't fall over that range. however it's still, a very limited portion of the math in a frame, that's not even ALU limited in the first place, so I doubt you are going to see any meaningful gain unless you are completely ALU bound and missing your target framerate by a few ms.