The main issue with IRC is that you have to stay connected all the time to recieve messages, and you have to leave your IRC client to see and search the logs (unless you have some intermediate IRC client server that runs all the time). It's just not as nice.
Yet it's not something that IRC provides out of the box.
I've got no issues running my own ZNC bouncer, but when you're choosing a product that an entire organization will use (including people who have no idea what "ZNC" means other than 3 letters), IRC is lacking a lot of features that get mentioned in every HN chat solution thread.
Yeah but if you suspend your machine doesn't it stop accepting connections? I personally set up a tmux window on a raspberry pi for this, but it's too much to expect a whole company to manage this (vs. a nice simple web GUI like slack)
