The problem with respacing a Shimano cassette is that a 10sp Shimano hub is too narrow and does not line up if you can manage to put it together. If you do 10sp with spacers on an 11sp hub it works because there is extra space. But that's the rub. If you have an 11sp wheel you likely also have an 11sp setup. And if you don't have the setup why would you buy a wheel just to make this work?
I did the spacers on my trainer because it came with an 11sp freehub but my bike was Campy 10. An 11sp freehub is 1.8mm wider than the 7-8-9 hubs and 1mm wider than a 10sp Shimano. I wouldn't do it on a wheel though. I was an early buyer of the Wahoo Kickr Core trainer and they hadn't made them with a Campy hub, but I think they do now. But 11sp is cross compatible anyway.
It's a 15 year old thread. They didn't have 11sp wheels to build on. That's why all of these kluges were needed. The Shiftmate may have worked, but the shop I bought my 10sp Campy bike from told me to just buy a Campy wheel. Why spend $3500 on a new bike and then depend on a kluge?