A local shop here experimented with quench gap and when the gap got down to .025" the pistons would juuust kiss the heads under circle track racing conditions, revving to around 7-8k RPM. Pistons rock and expansion rates vary between engine parts, so I take that as an absolute racing minimum. For most folks, I'd recommend the .035" minimum.
I agree with Crackedback..... .050" quench gap still gives some benefit from all I have read on the subject for 40+ years.
As for the benefit of quench: I like to run CR as high as possible to extend the torque band down as low as I can; that is all due to my street use and rally experience. Quench just gives some margin against detonation, and thus some margin against things going wrong as one drives around with variable gasoline, etc. It also contributes to a small amount of combustion efficiency, and thus power and mileage.
But, I can see others deciding to forego it.