I have seen one in person, (didn't get to try it), and these are the perfect solution to an expensive installation of a bidet, providing you even have the space for one.
In fact these are even much better, as after they wash, they also dry... I believe the Japanese first came out with these, and became extremely popular over there, then spread throughout Europe, and now in the U.S., with many distributors and dealers offering them, as well as knockoff models.
One model features a convenient wall mounted controller, which actually electrically raises and lowers both the seat and lid. Considering the cost of a bidet, (about the same when I looked at them), these are a much better alternative as there is no additional plumbing to be installed, not to mention those costs involved, and again providing you have the space.
When I remodeled my bathroom, I had planned on installing the matching bidet to my new toilet, but just plain ran out of space.
You can google 'Japanese toilet', and even find u-tube videos of these. While browsing around I came across a Japanese colonic giver as well. Not unlike those do-it-yourself home colonic boards, at least in principle...
This was a very large, entirely self contained unit that you lay 'in', instead of on. Again, very large, probably taking up a bit more floor space than a typical tub shower combination.
Ah... if we all only had that extra, say 100 square feet of space in our homes, (and some extra bucks for remodeling), just imagine all the possibilities! Would probably be a good topic for a new thread.
Personally I would certainly include a large tiled 'wet area' just for doing enemas and colonics, with a large two inch drain for flushing waste, multiple shower heads, maybe one of those 'surround' shower heads, that goes from head to toe, and of course radiant heating behind the tile to keep it nice and toasty in there!
Getting back to the toilet seat bidet, certainly the thing of the future! Have no doubt that all new construction homes will include these in the future. Their popularity is spreading across the 'world'.
I'm sure will pay for themselves in the first year just in the cost of toilet paper!