I am pretty sure that those machines aren't legal but there is much corruption in my country so I bet there is some big fishes making money on bribery allowing that those machines keep working on the corner stores.
Basically, what I know of such machines are that they are used for games. Coins are slot inside to activate access to the games and kids play on them, except if they are now used to do staking and competition for profit or gains. Otherwise, they are machines that children play around with for their different games and those coins are so that it allows access to it and timing for the games.
So apart from that, except there are people who now arrange them for the purpose of gambling for underage.