The server/channel listings, do not work for most because of the simple fact that, most people are invited to IRC by friends, who pretty much say '
Go download this
and type /server whatever
and /join #whatever'
But for people who have read some forum, or general information about IRC and find mIRC, the server/channel listing is a valuable resource to finding a "decent" server/channel.
Although, being the "default" server (gamesnet is atm i think), is a sure fire way of being noticed, as most people who are new to IRC tend to stay on the default server.