The hero skins that were brought over from Battlegrounds mode don’t have their own unique voice lines. Instead, they use the exact same voice lines as other already existing hero skins.
They do that a lot. Only “premium” skins (or whatever they call them) get new voicelines.
No. There are so-called Tier 1 and Tier 2 skins — and more recently, even diamond and mythic — but every hero skin used to have its own voice lines.
Not anymore, obviously.
When they introduced reward tracks for expansions (starting with Darkmoon Faire back in 2020), the number of hero skins increased rapidly. Some of the newly added skins reused the same voice lines as the basic hero skins, and the community responded with a outcry, saying they didn’t want that.
Ever since then, they made sure to give every playable skin in traditional Hearthstone mode its own unique voice lines. But now that has changed, and I think it’s a step in the wrong direction.
Well, yes. So?
PS Or, I suppose, you’ve already made your point in the next post — alright, then, I responded below.
Some (or should I say ‘most’?) of the ‘less premium’ skins get unique lines, some don’t.
More about that later (just below).
Only if you are a hearthstonetopdecks.com dweller. 
If one wants more or less official terminology, there’re ‘full’ and ‘lite’ skins — such official wording first spotted here, as far as I know, but there’s also this breadkown:
https://hearthstone.wiki.gg/wiki/Hero_skin#Rarities
I see. Perhaps they’ve changed their mind or could no longer ensure that, forgotten, lied, the people responsible for that have been layed off or whatever.
They really need to double down on their focus on flavor/lore in Hearthstone. In this expansion they seem to be going in right direction overall.
Unique hero emotes fall into this category to me.