Some smaller platforms might have unique games you won't see elsewhere, communities more suited for the kind of person you are. Or more personalized service.
Smaller platforms put more work in their customer service and that's why many people get attracted to them, they're new so they'll be looking for ways to get people to use their casinos, which will make them very nice in attending to their customers.
This behavior make their customers not to suspect a thing when they're using the casinos, they might include games that aren't available on other casino sites and have bonuses that'll attract people and they start preferring to use the casino.
With the customers caught up in all this good experience offerred by the minor sites, then they take advantage of that and scam them, this steps can be repeated again with a new casino and they'll be successful because humans can be easily deceive