As we know, guess, experience … not everything is what it seems.
For example we may gain wisdom/compassion from a dead fly or remain ignorant of our transitioning being. There are many examples amongst us of useless and useful teachings and teachers.
We have to develop discernment, otherwise we settle for celebrity gurus/new age flim flam/incompetent 'spiritual' influencers and incomplete 'teachers'.
So what is useful? For me it is the tried and tested.