Why not a Network based POW algorithm

[alquinte]

So when looking at POW algorithms I stumbled upon this guy on wikipedia: http://en.wikipedia.org/wiki/Guided_tour_puzzle_protocol

Has an alt coin ever been made with this idea in mind? If not would it be possible?
It looks like it could be a fair way to distribute coins without taking up so much computer resources (although I guess it could become a bandwidth arms-race instead). You guys have any thoughts on benefits/drawbacks?