I am going to try them this year in my tires. I think it's a good idea and will eventually catch on.
As far as buying tires on line with the beads installed. I wouldn't buy any tire online. Most discount tires have defects and don't come with warranty.
It's really easy to ruin a tire simply by installing it also. Most non contact machines you need to be extra careful. Many times I've seen tires being stretched to far to get mounted on the rim cause the installer wasn't paying close attention to the opposite side of the the tire. When installing most people pay too much at tension to the arm pulling the tire around the rim and not enough at tension goes to the opposite side of tire, that side needs to be in the drop center of the rim, if not the tire will tear. Sometimes you can't even here the bead tear when installing over the flange of the rim. Some of the machines have a nylon wheel that presses on the bead and rotates around the wheel. If the tire happens to get pinched between the wheel and bead that can also tear a tire.