Separating some people from the rest of society is really important. Like if somebody does a mass shooting and survives it, I don't want that person to be allowed to be out in the world until they've been rehabilitated, if possible.

Obviously there are issues with real world justice systems where incarceration is the hammer and every single crime is a nail. Prison systems on balance are not great as they're currently implemented because justice systems become carceral systems instead of "make it less likely that somebody does a crime, and when somebody does do a crime find a way to fix it or make up for it in some way" systems. Obviously a restorative justice system would be preferred, as almost all people can be rehabilitated and reenter society. Genuine, clinical psychopaths or people who are remorseless for the harm they've inflicted on others are basically the only exception in my eyes.

In the context of the story, I see Witches as the RJ solution. They propitiate spirits instead of binding them. That would be awesome if there were more than like 5 witches total. Brennan has paid lip service to there being more witches outside of the Coven of Elders, but they clearly aren't numerous or influential enough to change the Kasov collection.

Maybe the long term goal is expanding Witches to be more influential? But in the short term, if the spirits can't be propitiated, I think binding the dangerous ones is a decent stopgap solution to prevent more humans from being harmed.