Some salesmen put some time behind it, not judged by a youtube video (which didn't demonstrate the wand all that well).
The Zipper has more flexibility that an RX, and it has no cord, that cord would be a PITA on a huge ballroom. On light soil you could walk forward like a lawn mower, making 50' passes, and just zipper stroke over 15" and walk backwards and slow down for the nasty stuff, it really doesn't need a dry pass as that is what the second wand slot is for. It would give your arms a break on 20,000 sq. ft. job, that is for sure.
Using it on a 10' patch of renter grade cut pile at a 3 day show is not a really good judge of a piece of equip.