I am not going to name other casinos, to prevent marketing them on this topic, but I have seen some other bigger names in crypto gambling world end up with those boring old style marketing as well, which is a mistake if you ask me.
The more they grew, the more that old type of billboard, sponsorship and all that marketing they have started doing, not realizing, if they spent 10+ million on online marketing instead of just those branding stuff, they would have been much bigger. Thankfully, 1win isn't doing that, they are aware that giving money to other companies isn't the way to do marketing, giving money to players is the reason why they are growing this much and that should be the most important part of the world.
They use old style marketing programs which can be because they see those programs worked well for them in the past. It's very likely reason but maybe there is another reason, that they saw it on other platforms and copied it to their own but I believe this reason is less likely actual reason.
Mostly old program styles can work well but sometimes in innovative game changing time, those old style programs fail and companies spent huge budget for nothing like this can collapse. Marketing is hard and complicated with any company even big ones as money if is used for bad and inefficient programs will be like burning and it harms the company too.