Even data centers have to use fake Halon, recycled Halon or CO2 these days. The Data center guys, the real pro's, try to find a way yo get the real thing becuase it is so "easy".

Short version is that halon could be dispersed in bulk from relatively smal nozzles with no freeze-ups. It did not take careful planning to flood a room with halon quick enough to save the servers. It also settled and "mixed" faster so the room would drop below an O2 level high enough to sustain fire.

CO2 is a different matter. It has to have large, well placed nozzles and lower delivery pressures to avoid freeze-up. They also seem to require larger tanks for the same wight of gas but that might just be modern safety standards.

I love Halon and wish someone would come up with and non ozone depleting alternative that does what Halon does.

FYI, the Air Force used Halon for everything. There was (maybe still is) a stack of asbestos wrapped halon bottle that have to whetted daily at an HAZMAT salvage yard in Altus, OK. In spite of the very high value of the halon once reclaimed no one could be found that had both the asbestos abatement certs and Halon recycling cert to handle them. The salvage operator was being paid daily for storage but he estimated there was over 3 tons of gas...