Well the specific discussion was exactly about keeping more than 4 copies of a card that is at mythic. Prior to the ascension mechanic, there was no reason at all to keep more than 4 copies. But then the ascension mechanic changed the rules - and folks who had been accumulating cards that were, as far as anyone knew, “junk” were suddenly rewarded greatly for their habits.
So the introduction of that system added a bit of a “I should hold extra copies even when they promise I won’t need them” attitude. And I wanted to reassure folks that we wouldn’t repeat the mistakes of the past, and that they should believe us when we tell them they can disenchant safely. I’d actually be in favor of an “automatic disenchant” function, that simply gives you the souls when you open chests and get cards you have 4 of at mythic.
The other potential example would be if someone did something extreme to earn a specific resource - souls, for example, and then continued to hurt themselves once they had no further need of an excess. For example, Arcane Mountain (yellow/brown) stones are needed for both Maw and Gorgotha, which are both great troops to trait up. If someone spent a bunch of money/maps/games trying to get a ton of Arcane Mountains, I totally understand. But if they then continued to accumulate those specific stones - to the detriment of others - reasoning that any future Brown/Yellow troops would be overpowered… well that starts to creep into “unhealthy” territory.
A fabricated example, obviously. But I think it makes the esoteric point.