Fun stuff. We had a halon system at a place I worked. Thankfully, it's never gone off on my watch.
We deal with much larger infrastructure now at my current job and we don't have any systems like that, I think there's just too many buildings/rooms to protect and it is cost prohibitive vs just dealing with risk if something does go wrong. They have fire sprinklers everywhere for life safety and that's about it. I do recall a story of a tech accidentally dropping a wrench on battery terminals and the fire sprinkler went off and saved his life. All the equipment was toast from the explosion anyway so adding water to the mix is not going to make it any worse. I'd hate to be the one having to go clean up that mess after.