Offline or online casinos, they already know how to attract more patrons on their site. Not only the games but the perks involved. But for offline casinos, I believe it is the actual experience that people mostly are after as they have social angle covered.
Not only the experience is different in land-based casinos, but you are having first-hand experience of the game itself. And some people are up to that kind of interaction. Aside from entertainment, they are also after for the food/drinks and other social aspect of this activity. Sometimes, it goes beyond gambling why some of them are visiting land-based casinos.
The perks offered by casinos are indeed the main attraction for their gamblers. The potential for big wins is certainly an attraction for gamblers to try their luck. I think it works in addition to the promotional bonuses given at the beginning for new users or bonuses that can be given to gamblers who reach a certain level of betting.
Offline casinos provide something different to gamblers. They have their own fans even though currently there are quite a lot of gamblers who choose online casinos. Not a few will still come to offline casinos.