If I forget to turn it on I always why I feel so gloomy.
Seriously get one, even if your lighting is otherwise nice.
The only benefit I can see is if you cannot touch type and need to see your hands, but isn't key lighting the normal solution to that problem?
PS - I used to work with someone that needed the overhead light on to see their LCD monitor better. I'm still confused by that to this day.
As for cost, yeah it's a bit much for what it is, but the build quality reflects that. The counterweight on the back is quite nice and solid feeling.