Rotary Hand Exertions

Realize, at once, the important fact, that such continuously resting srm-weight on the key-beds (as in weight-transfer touch), although still light, in turn also compels you to exert your hand continuously

In short: The main distinction between weight-transfer and arm-vibration lies in the 1) continuity or 2) discontinuity of the hand exertions.

When using weight-transfer touch you have continuously applied hand-pressures (the degree of which is determined by the amount of weight carried), whereas, with arm-vibration, the hand-exertions are applied individually for each finger during key-descent only.
This would indeed be much simpler, if we had ten hands instead of only two. Such continuously "passed-on" weight and hand-force may again be slightly increased to correspond to the required degree of tone.

Moreover, such continuously passed-on weight may compel the forearm rotational-stresses to be continuously applied for a series of notes at a time proceeding in the same direction. During practice, the individual rotatory motions must be anlayzed with respect to their direction. When performing using weight transfer touch, the rotational stresses are still present but not visible.

In short, with "Passing-on" or weight-transfer touch, we can practically only have "Mass-production" effects, represented by swirls of crescendo and diminuendo, produced by the respective gradual increases or decreases of this passed-on weight-basis.
Therefore strictly avoid "Weight-transfer" touch for all passages which need every note to be musically individualized that is, for all melodic passages. Since melodic passages always require meticulous selectivity of tone and duration for every note.