Kind of silly given that the new Macbook Pro Air HD Super 15 has a better display than anything else I own, so I'm not going to necessarily want to put a 1920x1200 24" or even 2560x1600 30" in the center of my desk with it -- I'd treat the laptop display as primary, on a stand, with a keyboard. But Apple doesn't make a docking solution, and the Belkin/Matrox docks have been vaporware for over a year.
Their thunderbolt ethernet adapter is $30: http://store.apple.com/us/product/MD463ZM/A
Even when setting up hotdesks for guests, it's unclear if you could put just a TB display in them -- enough people will have non-TB macs, or non-macs, to require something else. Maybe you could have some percentage TB display, but a good third-party dock + a display which can take multiple inputs (DVI, HDMI, MDP via adapter, TB to adapter to monitor) seems like a better choice. Uglier, yes.
For personal/home use in a dark room with only 2011+ macs, and if you have a spare 15" for other temporary use, then sure, it's a good option.
Keys/wallet/etc. remain in pockets when not in use, though -- so they're a LOT less likely to be abandoned than something which is small, connected to another long cable, etc.
Presumably the logic is that its all wifi these days anyway.