Lazy allocation
..that's what this sounds like to me at least- and for general purpose storage that will presumably have exactly the same problems as that normally engenders unless the book-keeping is kept up to date, e.g. your 100TB allocations are reduced to 25TB and the 1PB array reckons it can fit 40 of those in... fine, until anything is written to a bunch of them.
"It should appeal to IT budget holders averse to paying for nothing" ... but you're not necessarily paying for nothing are you ?... you still can't safely put any more data into the array because you run the risk of over-allocation. It'll make moving the volumes about much quicker though, and so could be useful for the snapshots and volumes for re-export only, but it doesn't stand up to their more general claims of the storage array being more efficient than another.