Like most innovations, the tubeless conversion seems targeted at competition. The selection of tires available turned me off. I have used Stan's sealant in my tubes this year. I've had 5 punctures and only one flat. The four times they didn't go flat, the tires lost enough air to get squishy. I removed whatever was in the tire, pumped them up and went on my way. The one that went flat was penetrated by something through the center tread and kevlar belt of a Schwalbe Big Ben tire, went through the optional anti-puncture I had put in and left a hole in the tube that Stan's would not seal. I still carry a tube. The sealant seems to be a nice convenience, 4 out of 5 is not a bad run at this point.
Marc