With how often people break or lose their phones, there will be some big thinking as to why you're giving someone who only works at a desk a smartphone for a computer. Yes, people who are more mobile will get benefits from it, but not everyone is that mobile. In addition, the no-contract costs of smart phones is quite high, easily comparable or higher than a desktop. Additionally, there's lifespan. We have several desktops that have lasted 4 or 5 years, and we still use them (while admittedly, they are quite slow) because they still do what's needed.

Oh and last of finally, when thinking of moving to a smartphone for a PC... Employee theft? All they have to do is wipe the memory and they have a black market ready phone, just replace the SIM card and you're good to go. (the non-removable SIM in the iPhone finally can be advertised as a feature!)

At least they're easier to support. Software issues? Wipe and reimage. Hardware issues? Replace.