Why is that relevant? What I claimed is still true: in Hearthstone, having a minion type is considered a beneficial effect. That's why cards like Puddlestomper (3/2 murloc) and Bloodfen Raptor (3/2 beast) can coexist as neutrals alongside cards like Knife Juggler (3/2 with triggered upside) and Wild Pyromancer (3/2 with triggered upside).
It is pretty relevant. Either "strictly better" means "strictly better in isolation" or "strictly better with all the other cards". You can't cherry pick which cards, otherwise every card is strictly better than every card.
I don't understand the point you are trying to make. Tell me which of these you disagree with:
- In Hearthstone, having a minion type is considered beneficial, compared to not having a minion type.
- Murloc Tinyfin is the same as Wisp apart from having a minion type added.
- The standard CCG/MTG definition of strictly better.
My best guess at what you're arguing is that having a minion type is not beneficial. My counter-argument is, Bloodfen Raptor (neutral 2 mana 3/2 beast) and Wild Pyromancer (neutral 2 mana 3/2 with a triggered upside) were both cards in the initial release, and it's clear (to me at least) that the balance idea was that "being a beast" and "having a triggered upside" are both considered beneficial additions to a card.
But let's say you don't trust the balance within a single release. (Although I think they've been careful to not release neutrals with a strictly-better relationship at the same time.) If you then ask "how do we really know that having a minion type is beneficial without considering other cards?", I'd say that it's a fundamental design decision of Hearthstone that every minion type has significantly more cards that benefit from that type than that punish having that type. The minion types are Beast, Demon, Dragon, Mech, Murloc, Pirate, Totem. All of these have notable synergies with the minion type (examples: Houndmaster, Mal'Ganis, Blackwing Corruptor, Tinkertown Technician, Murloc Warleader, Southsea Captain, Thunder Bluff Valiant). Only the strongest minion types have hate cards, and they are all pretty much unplayably bad (examples: Hemet Nesingwary for beasts, Sacrificial Pact for demons, Hungry Crab for murlocs).
The only place I can see to go from there is to say, "well, what if there were no other cards in the entire game", because it's clear that if there _are_, then there are definitely going to be synergies with minion type, at least for murloc and beast. (Some of the other minion types didn't have synergies at time of release, although they didn't have anti-synergies either at that time IIRC.) But if that's the assumption we're using, then Wild Pyromancer's effect is also not beneficial, since if we pretend there are no other cards in the game, then there are no spells in the game. It becomes an absurd standard to use to judge cards.
Remember that definitions are chosen to be useful. If we were to choose a definition of "beneficial" that excluded a lot of effects that are obviously beneficial, that would not be a useful definition.