Tal If it’s high on one side of the basket, i.e the coffee isn’t distributed evenly, then during tamping, the tamper will displace coffee until its level anyway, coffee isn’t cohesive when dry, it will simply move beneath the tamper and spread to fill the basket until it’s fully consolidated and all voids are removed.
Likewise any clumps, break them up if you like with WDT, but they are all going to be forced together again under the tamper.
So, I can see this falling down when insufficient pressure is exerted during tamping, such that voids can remain and any clumping may still have an effect. But as long as you fully consolidate the puck, what does WDT do that won’t be undone anyway during tamping?
There has been a lot written about this and tested over the decades, but bear in mind that attraction between particles may not be totally negated by the act of tamping. Particles will be forced into closer proximity with each other, but attraction and repulsion between particles may still remain, allowing for channeling/less even flow across the puck.
Tamping does not remove all voids, nor do we want it to. The puck must remain somewhat permeable to allow flow evenly through it and for the coffee to brew without choking, nor fracturing the puck, nor leaving dry spots . In pre-infusion/filling of the brew chamber, low pressure water will fill these voids and maintain them, as water cannot be compressed. As the shot brews, the puck will be eroded by the flow of water washing out coffee solubles (remember, the dry puck should weigh around 20% less by the time the shot is completed). Due to erosion, voids will grow. Again, if there is a cause of severe unevenness, this can exacerbate uneven/low/inefficient extraction.
Is any of this particularly relevant to WDT, shaking, or RDT, as opposed to adequate distribution in general? Try them all, go with the workflow you prefer as long as cup quality is not noticeably degraded. I doubt there will ever be consensus as to which is universally preferred, none of the options require great expenditure, nor years of your life to be wasted.