I believe this is more of a self paid promotion anyway, you are getting customers and you are not paying a single thing for it upfront. Affiliate is far better than signature if you are looking for just efficient and optimized profitability. What casinos do when they get a signature campaign is actually just getting their name out there, its not about getting new customers only, of course that is a big part of it but they want to be known and get a community behind their casino.
However, wolf.bet is already known and liked by many people and even the people who do not play here knows about here. So now that the name is out there, the best case would be affiliate, that way people could invite others and casino can have more gamblers and they would only share a part of their profit instead of paying money without expecting anything.
There are no best type of promotions that explained by old casinos have different types of promotions run at the same time. They run their promotions via their signature campaigns, affiliate programs, Telegram give aways, Wager contest, bonus for deposits, etc.
If you judge affliate program is always better than signature campaign, it is not true and I disagree with. Which one is better, the team know it well because they have data from their promotions. We only guess, but they have data.
All types of promotions need time to have effects, especially for young casinos. Games on casino also play important role to attract gamblers.