Purchasing traffic is a good idea?.

Even for new sites/blogs?. That kind of traffic has a very high bounce rate and i don't think you will get any returning visitors.
For a clean, user friendly place, without lots of crappy ads I see no advantage in having 5-6k daily visitors you just purchased.
Will it help the site/blog in any other way I can't think of?.
I know content is king but i think it is of little use when your visitors are sent there as part of a traffic package you just bought.