reasons kosuzu motoori should be an honorary member of the secret sealing club
  1. passionate
  2. loves to collect dangerous materials that most people would not touch with a 20ft pole
  3. gets involved in supernatural hijinks on the regular
  4. will add a new exciting hair colour to the group
  5. opportunity to receive a fancy new hat for herself as a badge of membership (i assume fancy hats are a badge of membership for the secret sealing club)
  6. her ability gives her access to a lot of extremely specialized but frankly useless knowledge, so she will fit right in