I don't find extremely compelling arguments, but there's points to be made. Having a phone that's also your computer is convenient, so having a desktop/laptop dock for your phone that would seemlessly interface would be an interesting take. Remove the $900 work laptop and instead purchase a smartphone capable of everything you need for your business. Most employers provide smartphones already, so if you can manage the ecosystem for the company standards, you could effectively cut your costs in half for every employee.
Plus, licensing costs would also drop, having only one device rather than two. A phone that requires a license on top of the work computer is just doubling cost. A single device has a single license.
Honestly, I see how it could be useful, but the arguments aren't exactly convincing. At a personal level, I could see how a strong smartphone could be beneficial to have as a simple docking solution whether I go to work or home, plus constantly having it charged would be nice- Those lapdocks have batteries that charge the phone while it operates, same for desktop dock solutions.
All in all, I'd buy into it if I liked the ecosystem the phone offered at every level- but now you need to convince me on how the application offering is for Android/iOs/Windows/Ubuntu on likely ARM devices in terms of mobile applications, scaling up to desktop applications.