The big feature I like about the tubliss concept if it works is proper rim locking. I always seem to be moving the tyre back around to avoid ripping the valve stem out. From what I can tell, even if the tyre does move, the valve stays put.
I think that the tubliss site summarises nicely the advantages, just got to prove them in the field. Dirt bikes seem to be one of the only machines that still use tubed tyres, tubeless have been the way to go for years on everything else.
Steve