Well if you're going to put it on a desk and plug it into the wall... it's a less powerful, less expandable, vastly more expensive desktop. You buy special adapters for your extra screens/peripherals, and spend time with setup/breakdown every time. I personally hate to share wifi with a dozen other people in my office so I need yet another adapter for ethernet (some notebooks have this, some do not).

When you unplug you lose all that equivalent experience, and then you're on battery power... which sucks for powerful laptops. Working from a couch or whatever just seems ineffectual to my workflow. I can see media consumption working in that case, (not the latest games of course) but then you don't need the big beefy machine.

I really don't see the benefit of portability for a workstation. It's a luxury to me when I have less things to haul around. For work everything is either in off site backup or version control systems. Obviously that wouldn't work for something like video editing.. but then (and I'm not an expert) you'd want a bigass power hungry workstation anyway.

Regarding apple notebooks: Bluetooth keyboards are pretty much equivalent to Macbook keys, so most of my co-workers would just use that. The apple mice suck, so most would again use the notebook trackpad. External screens were used as expanded desktops with most work happening on the default notebook screen. Everyone was hunched over the laptop like it wasn't docked at all. This is my own limited experience, but it seems that in practical use, the limits of laptops somewhat encourage poor ergonomics.