Second Life a must for planners?

I am a bit of a sceptic about Second Life, but even I recognise that it has huge value for any public body that is planning a new building or redesigning an area. Thanks to Dave Briggs, I came across this useful summary of Birmingham's use of virtual worlds for just these planning processes - http://ideaperformance.com/2009/01/27/birmingham-and-second-life/