On May 1st we had a first giveaway (3 TotG packs + 3 Arena tickets) because of our "patience" (you know, the reconnecting feature).
Immediately, HS gives away 3 packs to celebrate 70 millions players. I used to play HS really some times ago... and I remember that such giveaways were not exactly "common".
Then SV gives away 9 packs to celebrate 9 millions downloads. And, instead of the classic "login additional bonus" (like the one we have seen during the "8 millions downloads" giveaway), we just get a bunch of tickets in our crate.
Maybe I am just overthinking, but I feel that this is more like a "giveaway war" between Blizzard and Cygames.
Cygames gave away 3 packs because they made us wait quite some time for the reconnecting feature.
Then immediately Blizzard gave away 3 packs as well. To me, this sounded like "Hey, we can be generous too, it's not true that SV is beginner friendly while HS is not!".
And then again, Cygames gives away 9 packs. And they did it in a very different way from the last one: no new login screen implemented, just tickets in the crate... as if they were in a hurry. And this sounded like: "Blizzard isn't generous enough. See? It's Cygames who is really generous!".
Thoughts?

I very much doubt either side cares much. Blizzard are too big to fight it out with other card games, and Cygames are busy figuring out how to add more waifu cards to the game, probably in the form of tanks/ships that evolve into girls.