Not to mention people who use facebook only through the phone app are not likely to ever search for facebook on google. I'm often amazed at how almost-completely phones have replaced "desktop computers" for many people I know (Anecdotal, I know).
Thus they may derive a benefit from staying at the office during the evening rather than going home to a smaller space and no computer.
A nicely designed all-in-one PC is a lot more palatable and manageable to the average person than the old tower/cables/monitor/speakers/etc.