YInMn blue does not fade, is non-toxic and has high opacity. It was approved in 2017 for industrial applications as it reflects heat and has commercial applications. It was finally approved last year for use in artists' materials.
I recently purchased a sample of YinMn blue in watercolor. I applied it to hot press watercolor paper using hatched strokes, building up to achieve a strong blue. I tested Sennelier ultramarine deep, Sennelier ultramarine light, Sennelier cobalt, Daniel Smith Lapis and of course YinMn blue.
YInMn dissolves well with water and there is no granulation. To my eye, it leans towards purple, and I found I could mix a reasonably comparable color using Sennelier ultramarine blue with Sennelier ultramarine violet. This might vary depending on the brand of paint.