I used this feature for 2 months with firmware 2017.50.12, TL;DR:
It works, but with numerous bugs, not recommend to use it right now.
Details I noticed with this option, there are 3 options: off, low, high
I'd imagining the low and high are apply volume enhance with different offsets. it's true, `high` setting does apply more offsets to volume, but here comes the covets:
It will constantly turn down your volume randomly, for example with high setting:
If your start volume is 5 with 0mph, it will gradually adjust to around 5.5 with 20mph which is noticeable, but stops at 6 even with 75mph, it's useless because of current tremendous wind noise.
but when you slow down to 0mph, it will reduced to somewhere around 4, which is below your original setting, this is definitely a bug.
And worst thing is sometime it even gradually reduced your volume to 0 after you parked for hours.
So I'd suggest you give this option a grain of salt, it's buggy and not work as it name suggest.