If you're one that can use it, it's a nice idea.
Robert Plant and Jimmy Page (drummer and bassist of Deep Purple, Jake!)
Handy for sure. It's either that or get a Gibson 2 point with switchable mutes in there ;P
I prefer the sound of over-string foam mute, playing with a pick it's different from under-string mute. For some reason only over-string keeps the click. With fingerstyle there's not a lot of difference. So I have one P with the cover and fixed mute, and one without. All lever-engaged mutes are under-string. This is the first time I see an over-string mute that can be removed in a second. Worth a try, I think.