I'm one of those people who wrote his own auto-hide script for the switchbar, so that it only displays channels that have active conversations (unread text in the last 2 hours; read text in the last 20 minutes). I have to impress that this is such a game changer in how I use mIRC and I could never go back to a cluttered switchbar.
That said, I don't personally hide the status windows myself, but I can appreciate people who do because I used to be one of those people who connected to 8 or 12 networks at a time. It would be psychologically upsetting to have this suddenly taken away after all these years.