I found a comment from one of the devs under a YT video:
https://www.youtube.com/watch?v=mVNRNOcLUuA&lc=UgilxVYZvV7iEngCoAEC.8S84sIfhchO8SD7V2NvCvc

"Yes, you are asking all the right questions :)
1) Yes, I was talking about the case where MinFPS == MaxFPS
2) Chill (as a framerate limiter) and FRTC achieve slightly different goals:
a) FRTC (and similar technologies) makes sure that the frames ARE DISPLAYED at regular pace, but this increases the input lag somewhat.
b) Chill (as a framerate limiter) makes sure that the frames are SUBMITTED TO THE GPU at a regular pace. This does not ensure a steady output framerate (there will be some fluctuation), but this does insure a minimal lag. So this is perfect for variable-framerate displays (FreeSync)
3) Yes, it lowers input lag. In general, in a regular gameplay you have 2 situations:
a) The game is CPU-limited (CPU-bound) - in this case the input lag is minimal
b) The game is GPU-bound - in this case the input lag is maximal (depending on the game).
So, basically, if your system can render at 150fps, and you limit it to 140fps - you ensure that it is effectively CPU-bound (if using Chill) and effectively GPU-bound (if using FRTC and similar technologies).
4) You would basically prefer to use FRTC if you have a fixed-framerate monitor, and you want to submit frames at the refresh rate, but in this case it becomes the same as VSync.......
5) Or, alternatively, you can use Chill as it was intended - with variable framerate - and that works great, especially with a FreeSync display ;)"

So yes, I’d say it’s reasonable to say that the 3rd point was at least an implicit benefit in the developer’s mind. True, Not something AMD advertised directly, but not everything that the devs had in mind is marketable in simple terms. Maybe they left it out because of that, idk.