My father listened for a few years before he passed. It was a pain, as there were three people on the line and you could hear everything everybody did or said. Also, if one of the other people hung up, he'd be disconneced as well, and if there was a new brother handling the phone and didn't know how to properly hook it up he'd be disconnected as well.
My mom and sis still use the system from time to time as well. I hated being there when it was on, and I found it even more difficult to listen to the meetings on the phone, it was sooooo boring!