Re: Workstation?
Because their jobs require actual computing power to do things like crunching sales numbers and the creation/manipulation of content, rather than Googling for the best price on a Carribean vacation or posting a few words of whimsy on the company Twitter (Yammer?) feed. Smartphones are only really good for voice/video messaging (try managing 500 e-mails a day on one), tablets are a child's toy.