I personally have never heard about it stopping "honk". I've seen people, and done that myself when you can hear the vibrations below the bridge and above the nut ringing out after you hit a note. This is very noticeable if you have a jazzmaster or other similar guitars, the strings behind the bridge make an audible noise after you stop playing. I have seen this more in the studio than live, but live with high volumes the strings ringing will be amplified, and for a cleaner mix they may feel the need to, especially with high gain.
It is made much worse if string trees aren't used on a non angled headstock as well.
Do it if you feel you need to, I wouldn't myself do it because my idols do, but if you are having issues with the strings behind the nut ringing when you stop strumming then do it. I used the foam from the boxes I got some of my BKPs in.