Having age restriction in online gambling and real life gambling is really important, kids should not be in the casino because that is so wrong for kids to be exposed in gambling because they are still not thinking so well. There are so many things that kids may do, more productive, more useful and knowledgeable, they may read some books, watch movies, bonding with family, play toys. That is greater compared to gambling.
Actually, age restriction in gambling is only applicable in real life as no one will identify if someone is wether underage or not as they can just lie. Although some kids who are below age based on their country's regulation were able to manage to sneak in casino as they look mature, the security in real life casino with regards to implenting that regulation is still tight and intact thus kids really focus more on studying rather than gambling.