You should not playing online gambling using your phones because you can get a problem from the authorities. If you want to playing gambling, maybe you can play when you are in your hotel and no one knows what you do. But that is not a suggestion because we don't know how strict they are with a tourist.
Yes, you should not gamble in public places, especially if you are close to the police station, it will get you in trouble.
But if you play in a place where there are no officers at all, people won't care.
Indonesia will not be as strict either, what you see in Berta about checking the phones of visitors or tourists is just a formality for a to-do list,
even though they will not do it every day LOL.
Indonesia don't have a local casinos so you will not find that in all cities. But if you can talk with local people, maybe they know something about underground casino.
And yes, if you ask the locals where the local casinos are hidden, they will tell you.
It was completely hidden, and only certain people could enter and know.
Rather than you are curious about local casinos, it is better to play on your mobile phone only, it will be safer.