Milled/ported slides on carry guns--what's the deal?

I am installing some upgrades to my main carry weapon, the Smith and Wesson Shield in 9mm, so I consulted the internet for some ideas of what people are putting on theirs. I came across not a couple, but SEVERAL photos of people milling holes and gaps in their slides (so the barrel is exposed). I am not sure if the barrels are ported as well, but i suspect not.Other than negligible weight differences, is there any other benefit to milling a slide on a CCW? To me, you are running a huge risk of something becoming lodged in there, especially if you happen to drop your firearm in the dirt or mud, rendering it out of battery potentially. Does anyone else have thoughts? via /r/CCW http://ift.tt/2lWeBka