I know right? Am I missing something here? What does this server offer extra that would explain the hefty $20p/mo pricing? I can just open a free private IRC channel on any server and use that?
Some measure of privacy & control.
Of course, if you care enough about that you shouldn't be using any exterior service.
Let's say you have a developer whose time is worth $120/hr to you. If that developer spends two hours futzing with configuring an irc channel in a year and no time futzing with this service then it has paid for itself without needing to offer anything extra. It seems like they're attempting some extra features to sweeten the deal anyway.
Describe "on any server". Like a $20/m AWS micro?
On any IRC server. There's absolutely no reason to host your own.