On what grounds do you conclude that gambling is currently attracting children? I am in contact with a lot of people and I have never heard any of them say that their child has a gambling problem. There are problems with some children being addicted to donating to various computer games, some are seen using vapes, but no one has ever told me that any of their children are addicted to sports betting, dice or slots.
Maybe those children don't tell to their parents that they are involve in gambling because no children will do that 
Even adults people will not tell to other people who don't close to them that they are attracted to gambling and involve inside gambling. They will have their way to hide their gambling activity from other people so they will not get any bad saying from adult people especially their parents.
But we know that gambling can lead to addicted to gambling if we can not treat gambling as an entertainment and a way to have fun. We already seen that happen to some people around us so we must be careful when playing gambling in offline or online casinos.
I agree with you, nowadays children are introduced to online gambling through such attractive advertisements. Due to the ease of gambling, children can easily access these casinos. And children are easily attracted to online casinos, and become addicted. Therefore, if parents are giving a device to their children, the parents should limit there children's internet usage. And keep an eye on every activity of internet usage. Overall, All parents must be extremely aware and it is important to monitor the online activities of their children.
They can see the attractive advertisement about gambling but they don't think that is a gambling. They just attract to follow the advertisements and clicking the link on that thing and visit the casino. If there are no understanding from the children how to use their devices properly, they will attract to gambling without they realize and if no one will know what they do, they can get addicted to gambling. Parents must control their children using their devices and always remind them about the danger of using the internet without control. Yes, parents must always monitor the online activities of their children so their children can use internet with right.