Lonewolf 50: As far as I recall it was done at medium levels to give a large enough manoeuvering margin to position the Unusual Attitude.
Certainly, with the nose high situation the rate of washoff of the speed can be so great the the extra authority of the THS is needed. It simply runs too slowly with the full forward elevator demand.
I have no knowledge of whether other airlines conducted such an exercise so can only speculate however the main training point about the possible need to use the THS manually was usually quite a shock to the students.
(caution: sim. fidelity alert here!)
EMIT: valid point - however we did not necessarily always do this exercise with wings level - often it was done with large bank angles associated with high nose-up attitudes.
I believe that the A320 `test flight` which crashed on approach to Perpignon also had a large THS nose-up situation which was made worse by the thrust-pitch couple with the selection of TOGA. Would the application of manually run forward THS have helped here? Maybe?