I'd actually say more works gets done, its encouraging creativity by allowing people to work in a place that invigorates the mind, Just think how bored you get when you're just stuck in one place, with the same scenery etc.
I kind of follow a similar kind of approach with my work, I don't 'work' on projects on a fixed '9-5', I work when I'm in the 'mood'. (I am available for phone calls though and work is always completed for deadlines!!)
I get twice as much work done if I actually am in that 'groove' rather than if I'm trying to force the work to get done within a set period of the day.
I would love to work in that sort of environment, but I'll never be in a position to see if it would improve my creativity! I can't afford the flashy furniture, and I'm not sure if the flat upstairs would be too pleased if I put in a connecting slide!
I'm more of a grinder with my work. Sometimes it comes easily sometimes it doesn't. But it always gets done.