Exactly what I thought. The technical "difficulty" of joining an IRC Channel through the ancient incantations of actually using a text-based interface instead of some fancy Webapp is enough of a deterrent to serve as basic divider between the people you want to have in a channel and the rest.
The barrier of entry to this thing seems to be the goodwill of "someone".
In my experience, there's an abundance of people just barely able to fire up their favorite IDE and hack something together in some kind of rapid prototyping web 2.7 thingamajig they don't even understand fully, preferrably using the latest JS(-based) framework and a (seemingly) random combination of currently hip "stack" technologies and packing all this on about 5 to 10 'cloud' instances without any knowledge of anything beyond the web.
So, while I agree with your 'Or at least, it's supposed to :)', there's an awful lot of people whose claim to 'Hackerdom' is going to some kind of 'Hacker School' or '-Weekend'.
Also worth noting, there have been at least three "let's chat" apps written specifically for the HN community.
I'm not saying we don't need another one, but when you have a free channel, then several other apps, you gotta wonder what the compelling reason for this one is.