It's a personal choice and a good number of people you expect to answer your question don't own a gambling business. But, looking at the lifestyles of gambling shop owners they mainly focus on running the business and attending to customer's problems. Not everyone feed on their product. It'll be at a minimal, as it'll look like cheating on themselves. When they win or lose, it doesn't count. Though, in the movies, gambling owners do participate in board games to at least keep their customers entertained. Hence, in real life, people tend to continue playing when they see the owner also participate in games. In other words, few of them don't gamble, but, when they do, it could be a marketing strategy.
not seen an owner sitting on the table to play but i guess to fill one chair i guess he can join so that it appears there are players. why not, they have money to spend. the baccarat game and the likes are like the owner/casino vs players.
they were hiring influencers to play on their website to promote the casino as well. the money used by the influencer comes from the owner, i think this is just like him playing in his own casino. the purpose is just different though.