Campaigns, promotions, partnerships, and collaborations with famous influencers would all be futile if the service quality offered will be compromised. Personally, I prefer having a decent experience with nice RTP because that's how you'll fully enjoy the game and the money you will place on a casino. Those partnerships and campaigns sure help them to encourage more customers or clients, but they better be sure that they are still providing the best services worth every penny. Because if not, clients will eventually lose interest and will have an urge to find a better casino offering what they are looking for.
It would be best if a casino would be able to balance the two. After all, it holds a factor in getting a client and making a client stay at the same time. It will just be up to them how they would do it.
^ Balance the two could be better or put weight on the RTP than the promotions or campaigns because when people try to test it they will surely enjoy it and stay on that platform once they like it and think that there is more beneficial to stay on that gambling casino because it has a high RTP that they can have. The combination of the two I think will cause to the casino becomes a faster-growing casino, as we can see many casinos doing that here and the more active these promotions with also have a high RTP will have a lot of users that stay for sure.