IRC has a lot of practical benefits, I agree. Unfortunately, it is a public medium over which I have no regulatory control. A lot of family unfriendly things go on there and I have no way to extirpate them from a Caudata.org channel since the channel would be part of IRC.
Yes, a bot can keep people out of the Caudata.org channel but I don't want to foster the use of IRC by, for example, teenage Caudata.org users, who wouldn't otherwise have used it.
I have a high preference for something I can ensure is moderated and separate from anything else on the Internet.