Nice. Horizon 4 looks gorgeous in 4k but I always play in the 60fps mode.
It's pretty cool when console games even offer a choice between 4k / 60fps, rocket league on Switch has the same sort of thing, either higher res/details or locked 60 but the visuals take the hit.
Choice is what it should be all about, give the user the option where they wanna shove the power and make it as easy as a tickbox of  Performance mode and most users will be happy with the choice.
Why not check me out on youtube and help me on the way to 2k subs over at www.youtube.com/stormcloudlive