I think Dan answered this question well, but would only add that many new hobbyists would very much like to know how to pick a tosai that will retain it’s beni so they do not end up with a shiro muji or bekko, even if the quality of the beni and its other attributes would not land it in the winners circle,
It boils down to this, if people are buying tosai, and they are, then it makes sense to teach tosai selection unless:
1. there are no criteria which can be meaningfully applied to selecting tosai; or
2. there are no criteria which can be meaningfully applied to selecting tosai that can be distinguished from the criteria used to select any other aged koi.
For my part, unless someone can demonstrate that either of those premises is true, I cannot accept the argument in opposition and I will not drink the water.
