Lloyd Evens said in this video, that he don't know, why bethelites became the chance to sit in the school for pionieers.
I think they will be prepared for their later dismissal and later work as pioneers in a congregation.
Neer 1:16:40 in this video Reino Kesk (Korea Branch Member) spoke about a couple, working since 50 years in fulltime service and never attended the pioneer school befor.