The role of the other alkaloids in the effect and satiation has been known (published but ignored) for decades.
It is not a new idea; it is the wrong turn that equated smoking with nicotine alone that needs to be corrected. That was a very serious mistake.
WTA is not the new thing, or the untested thing; nicotine used alone is what is new - and it is untested long-term. And it's not working out too well. For most people the satiation and the benefiits are not there; only overdosing to little effect.
Imo, the most important thing - and I think obvious thing - about WTA is the safety implication of the next paragraph.
WTA is what we have been using for decades, yet suddenly it was declared that nicotine is all that matters. That was a very irresponsible move.
I suggest that many people will get only some of the effects of nicotine - the stimulation, notably the adrenaline rush that leads to higher heart rate and blood pressure (and also raised dopamine), but not the balancing relaxation that depends on release of serotonin, endorphins and opiate-like pathways. This depends not on nicotine levels as many claim, but on rates of change that depend on the MAOIs; this is what is overlooked - it is not just levels that matter, but how quickly they change (for neurotransmitters particularly). That is why just ODing on nicotine does not, and cannot, do what WTA does (even aside from what the other alkaloids may do by themselves, besides modulating nicotine's effects).
The use of just-nicotine could lead to complications with high blood pressure, and psychological issues, that would not occur if use was in accordance with historical use.
Fortunately, most for whom nicotine-only is not going to work out give up on it before things get serious, but were WTA to be available as an alternative for e-liquid, the situation would be so much more favorable.
WTA is safer than just-nicotine for this reason (use of nicotine alone might sound safer, but is actually a step into the unknown).
WTA is also safer because the reduced need for intake reduces the intake of the co-administerds - with vaping, this is the PG / VG and flavorings.
In short, it is not the WTA approach that needs to defend itself, but the decision that nicotine was all, which we know is not the case; and the outcome of vapng, where most fail to succeed, confirms this.