Talking about operational costs, online gambling is certainly more friendly. Not all offline casinos are experienced. Some people seek pleasure and art in offline games. Offline gambling is more often done by people who are quite old. Enjoy the best games only at offline casinos.
Offline casino is fun when you gamble there because of the socialize aspect of it. The environment, music and everything makes it fun but their odd wouldn't be the same as an online casino that you don't have access to all those fun and entertainment.
Online casinos will give a better odd because that is how they can use to lure offline casino gamblers to try something new with a different experience.