We at my site sat in a conference and watch the slides moved and listened to the voice over the phone/intercom. Like many did at other sites.
Although there were those who seemed to feel that they needed to show how busy they were by calling in at their desks.
We had the internet die on the computer at our site during the part I was interested in so we could not see the slides, but we were still able to hear the presenter.
The real bad part came at the end, well one section until the end. Throughout the presentation we would hear phone button beeps and an automated voice saying that the phone was now unmuted. Well when we got to the next to last section of the presentation one of the phone in people put the presentation on hold!!! So all the off-site people and other phone ins got to hear musak instead of the presentation.
This would not have happened if were using SL. Although there might have been some crashes lol.