I would REALLY not complain about randomness and how bad those gifts are, since they are quite a big thing for ree. (of course you will do what you believe is right, just my opinion).
I don't see people saying the rewards are bad, just the randomness. Just because something is free doesn't mean that the manner in which it is delivered is beyond criticism. Historically, the Gwent playerbase has always been vocal on the subject of randomness in the game. If you were to build a pyschographic profile to represent the community, some of its traits would show strong inclination toward measurable, achievable progress-based reward systems. So implementing an random reward system is something that won't ever be well recieved.
I think CDPR has realised that the first iteration, the snowman in the yule event, was definitely to far off the beaten path. Hence this time around some of the randomness has been removed by having specific drop points tied to each daily crown win. Personally, while I get why they want to try new ideas, I think the sticking point will always be a randomly generated reward. What they would be better off doing is tying each desirable reward to a specific target, like X number of envelopes found, if they really want to go down the free lootbox path.
I believe better discussion is, what Chinese trinkets have to do with witcher (I'm ok with itI guess).
About as much as the Geralt: Ronin and Ciri and the Kitsune figurines have to do with it. Or the representations of Offir and Zerakania if you want to go purely from the lore per the books. And then if we go with holidays that have religious origins but have largely been co-opted by consumerism, Oktoberfest (Mahakam Ale Festival), Halloween (Saovine in Gwent) and Christmas (Yule/Mid-winter). Though, specifically for online games, it's more the last point that sees real world events shoe-horned into the game's microtransaction economy. Simply, people are primed to spend money (gift-giving/recieving, etc...) during those periods, so holding an in-game sale in the guise of a acknowledging the holiday just seeks to capitalise on that vibe.
However, to take the discussion away from retail pop-psychology, we musn't forget that CDPR own rights to the Witcher franchise. I don't really know what the specifics of the agreement they have with Sapowski on how they can use it. Since the Witcher games all take place after the book events, it does seem that they may create new content and IP based on the Witcher universe. This could involve creating new lore and locations that are analogs of places and customs that exist in our world. Given that Slavic culture and mythology are already built into the Witcher universe, It doesn't seem that far removed other cultures and mythologies could also be viable to expand and extend the franchise independently of Sapowski's books.