For the blindlight affinities, as far as we can know, only Mooneye has significant power in them. Also, she has a healing affinity to prevent cancers and radiation poisoning. Since the danger is limited to what she does to people, it doesn't have the same stigma. People are used to Great Powers with the ability to kill cities. Additionally, yellowstone (uranium) in this universe appears to be significantly more dangerous than it is in ours. It's not like picking up unenriched uranium will kill you quickly on Earth. We can also contain it better than seems possible on Anastist.
Affinities are tied to language, and radiation is very poorly understood on Anastis. Most of Mooneye's blindlight affinities are artificial; there's a good chance that blindlight affinities are almost unheard of outside of her (and most people who realized they had one would likely go to her for training).
Yellowstone, OTOH, is a material that most educated people have heard of. Natural yellowstone affinities are probably much more common. The effects of yellowstone are also known enough that there's a decent chance that people with weak radiation affinities would get called yellowstone mages anyways.
Another issue is that people have very little understanding of how to contain yellowstone. Blindlight can intuitively be protected against using the same methods as visual light. It's much easier for a blindlight mage to modify regular light spells than for a yellowstone mage to understand that their material is giving off radiation. Their combat spells would also be much more immediately lethal, if you base an ultraviolet affinity attack spell on a visual light attack spell, it's going to cause immediate damage with side affects if they survive. If you base a yellowstone attack off of attack spells from poisonous affinities, it's going to be a long, slow death.
For the blindlight affinities, as far as we can know, only Mooneye has significant power in them. Also, she has a healing affinity to prevent cancers and radiation poisoning. Since the danger is limited to what she does to people, it doesn't have the same stigma. People are used to Great Powers with the ability to kill cities. Additionally, yellowstone (uranium) in this universe appears to be significantly more dangerous than it is in ours. It's not like picking up unenriched uranium will kill you quickly on Earth. We can also contain it better than seems possible on Anastist.
Affinities are tied to language, and radiation is very poorly understood on Anastis. Most of Mooneye's blindlight affinities are artificial; there's a good chance that blindlight affinities are almost unheard of outside of her (and most people who realized they had one would likely go to her for training). Yellowstone, OTOH, is a material that most educated people have heard of. Natural yellowstone affinities are probably much more common. The effects of yellowstone are also known enough that there's a decent chance that people with weak radiation affinities would get called yellowstone mages anyways. Another issue is that people have very little understanding of how to contain yellowstone. Blindlight can intuitively be protected against using the same methods as visual light. It's much easier for a blindlight mage to modify regular light spells than for a yellowstone mage to understand that their material is giving off radiation. Their combat spells would also be much more immediately lethal, if you base an ultraviolet affinity attack spell on a visual light attack spell, it's going to cause immediate damage with side affects if they survive. If you base a yellowstone attack off of attack spells from poisonous affinities, it's going to be a long, slow death.