Cool or not...
...Steve doesn't want you to use a dock - There would be docks with an apple logo for sale if Steve approved them. He doesn't.
- Macbooks gather a lot of heat when the lid is closed. The forums are full of warnings that overheating is a reality.
- When the lid is closed the laptop enters power saving mode unless using 3rd party hack.
And of course there's the legion of Appletards who claim that docks are useless anyway if you happen to ask for them.