I just said that cards can't be strictly better if they don't share the same type. The reason they can't be strictly better is because there are lots of cards that care about type, so there are situations when you would, for example, prefer to have a Curse to a Copper.
It is possible there is a type pairing that doesn't actually matter, but I can't think of anything at the moment.
What is a plausible edge case where you would prefer a curse to a copper, barring Fairgrounds, Masquerade, etc.?
I mean, this is a question about what is and isn't allowed for this definition.
I think it is reasonable to restrict cases where the only reason you want one card over another is because it is a different card (Fairgrounds, Menagerie, ect) This is an obvious restriction because you aren't really preferring B over A, but rather preferring anything that is not A over A.
I think it is also reasonable to restrict cases where you want a worse card. (Possession, Masquerade, Opponent's Tribute, Ect.) I don't even think this case has any merit, because it isn't describing a case where card B is better than card A, but rather just a situation where you happen to prefer the card that is worse. (This should really cover situations where you would prefer to draw less cards due to shuffle timing also.)
The grey area is regarding cards that care about specific cards or types of cards. Does Tournament's existence make a VP card that costs $8 and is worth 7VP not strictly better than Province? I think people will have differing opinions here. If you don't think this one counts, then Awaclus' example doesn't either. Personally I think everything within the scope of the official cards is fair game outside of the above exclusions. Off the top of my head, Poor House is another reason to prefer Curse over Copper.
I think the only worthwhile discussion here is what is the point of "strictly better" in the first place. "Strictly better" is usually part of discussing how to properly price fan cards. If your card is strictly better than Laboratory (+2 cards +2 actions) you probably need to price it higher than $5 or add some sort of penalty.
But... Does this have any merit that "almost strictly better" doesn't. Probably not beyond puzzle threads like this one. No one is going to say that the $8/7VP Super Province is a good card just because you might prefer Province on a Tournament board.
So what's my point... I don't know anymore. Somehow I got into an argument about "strictly better". My opponents have the opinion (I think) that Copper is strictly better than Curse because the edge cases are too insignificant. My opinion is that strictly means no edge cases. Ultimately Witherweaver suggested that "not having another strictly better discussion is strictly better than having one" which I can certainly agree with.