If you use Quora you would see how it’s so easy to have category level user titles, editable by the users themselves. This helps in bringing value to your answer for your readers.
While Discourse has user titles they are workable only for small set of users as they need to be set manually by the admins or if done through badges they would be less relevant.
When discussing it really helps to know more about the poster just from the user titles. Even here on meta it’s very useful to see tester/co-founder etc as user titles as it implies they are the most resourceful but other users don’t seem to shine enough.