I think you have to watch out for sound bites, yep, it might work as a general rule, but there are situations when it doesn't. So make sure you understand why and when they do it don't just follow it blindly. Otherwise at some point you might hit one of the situations where it's not so good without realising it.
In that video they are all talking about fish that have been shipped to them or they ship out.
Shipping means the fish are often in a small volume of water for days, that means potentially the ph has lowered and ammonia built up, when you open the bag and expose it to fresh air, the ph rises again swapped the ammonia from safe to poisonous. That's why people that regularly receive/send big shipments of fish plop & drop. Leaving the fish in the bag whilst you drip acclimate exposes them to ammonia for a long time - that's a bigger issue than a change in water parameters.
Rachel O'Leary specifically says IF you are going from softer water into harder water it's safe to plop & drop.
In the comments of her own video she says "This IS specifically for shipped critters" and "With low pH- I do a very, very prolonged acclimation over several days" and "Generally speaking, if going into water of similar or higher TDS, the shock is very low. Going from high TDS to very low can cause issues".
And from her website:
"I have no issue with the drip method, but in order for it to really be effective, it should be done over a minimum of several hours.... From my experience, most hobbyists do not take enough time for drip acclimation to be less stressful than just adding the fish directly to the tank which is why I counsel to just add them quickly."
Ted Judy said if buying locally with no time for ammonia build up there is no danger to drip acclimating them in to bag if you want to.
So yes, if they've been shipped and ammonia is a potential issue, then that outweighs the other considerations - plop & drop.
If you have brought them from your local fish shop and you both use the same tap water then you are probably also safe plop & dropping (which is the most common situation and why people say 'I do it all the time and the fish are fine').
But, if they are sensitive species, or the fish shop water and your tank water may be different, particularly if the fish shop water is harder than yours (often the case if you use RO, rain water or remineralise shrimp water) then drip acclimating over hours or adjusting quarantine tanks over days won't hurt and can help.