The other point is that 100% efficiency isn't required to make beautiful planted tank. See Amano and Oliver Knott for example.
That is correct and I would just like to add that a needle wheel pump and a venturi works extremely well also but doesn't dissolve CO2 100% either.
I believe he still uses them because they look artful, and the dude's an artist. Him or his company designed them to look good in a tank, so he uses them in the tanks. I would also assume that he uses them because he sells them, and it wouldn't look too good for an aquascape company to be using a product that they don't sell.
Takashi Amano is a business man. That is the only reason he doesn't use a reactor. Producing, marketing and selling "his" products is what he is about, it's not a bad thing mind you, I think it is great that he does that.
Some of his products work very well while others fall short. It is all about selling the "Natural" aquarium system as ADA and that is fine with me. He sell his merchandise to make money, that includes his "glassware". Again nothing wrong with that.
Some people on this forum are simply planted tank farmers. They grow plants to simply grow plants in their tanks with little to no scape. Many are artistically challenged but somehow manage to grow plants very well while some are so called "artist" and can't grow the easiest plants available.
Amano markets everything he sells as a "Natural System" which mimics nature and therefore looks beautiful. Some call it art, some call it nature in a box while others drool all over themselves. In any event he does what he does extremely well. I believe there are very few people, if any, that can rival his style/personality and his ability to translate what he does so easily which almost always looks incredible.