Virtual Tours - do we need em?

I am pretty much a veteran realtor at this point. I'm a broker, have hundreds of sales under my belt and all the resume stuff that we all work toward. But I want to know how others are finding the virtual tour as a marketing tool. A friend of mine does tours here locally. I'd definitely use him: knoxtours.net but the question remains - is it worth the money to add it on? Will it increase the number of listings I get, increase the likelihood of a successful sale and all that.

Thanks!

Rob