Oh for sure. I'm generally not a huge fan of spam posts and as much I don't like to admit it, giveaways are absolutely spam. Thats not to say that there isn't a demand for this type of content but it doesn't really add much engagement to the platform.
I also agree with you. I think they were hoping more packs would sell and are now realizing that they won't in time for riftwatchers. This is now a method to ensure card scarcity via packs going out faster than they otherwise would.