Well, a subjective test, in a quiet room, with test tones for references is satisfactory for most purposes - if the system determines that it is unable to assess the situation, it can be escalated to an MD.
Exactly, just useful for a screening, but not for determining actual settings.
And there is more that is taken in to account when setting the hearing aids, such as:
Age
Speech comprehension issues
Loudness thresholds
cognitive issues
As well there are a handfull of "red flags" that are looked for, some of which can only be done with a visual examination, and others by more involved audiometric testing.
