Training centres in China, as shitty as they are, have no formal curricula, no value, and are useless - including the people they employ to collaborate in their charade. Public schools with formal curricula - not only in China, but also anywhere else in the world - will employ degree holders only to perform the work for which they were hired. That is the norm and should serve as a point of orientation.
All the rest of arguing why non-degree holders are "better" than degree holders and why they are useful in ESL is a load of crap.
The ESL industry on the whole in general is a load of crap.

ESL types who are both degree and non-degree holders have a hard time getting their messages across to people without having to rely on pre-existing knowledge to hold themselves up.