Well it's limited offer not forever.
Plus is gambling, even though they boosted the RTP. Still do users have some funds for gambling? or brave to losing some money. That's just showing how they really care to the holder. But still, IMO those kind of offer not gonna to make the casino lose
1. It's limited time frame offer
2. Not everyone have a money to gambling during the promotion (they could be just hold the asset)
Yes, and from what I saw in the links you posted, it's not available for all games. These past weeks, it was for Plinko, and it could change next week, which limits the games you can play. But still, as long as it lasts, you can take advantage of the offer, and unless variance goes against you, you can make a profit (as I said it's not just a simple 1%, a 1% edge in your favor compounds over multiple bets, just like a 1% edge against you can sometimes wipe you out in a single session).