I don't think it's a bad idea to educate your children about it since it's your choice and going to be your decision as a parent, but the main thing that I think that would be beneficial to focus on is why your family is working with cryptocurrency use when it's banned in your country. Do you think you can get in trouble knowing that idea? Would you want to bear that with your children? I don't think it's a good idea knowing that it's banned. Yes, you can educate them about it, but when you are talking about the legality and how it would work, it's definitely going to be a battle.
There are many legal people/police around us if they get any information about Bitcoin from the mouth of children then our elder family members will face many problems.
I think it's better that you don't involve them if you guys are on the verge of getting in trouble.
I cannot imagine living this life working on a certain thing that is considered illegal in one’s country. Maybe for now your family will be safe as no one has reported it yet, but if someone in your neighborhood will suspect that your family is still working on bitcoin, I guess your family will surely be in trouble. So my advice is that never teach the children for now as they can be very honest when asked by the officers roving around if your family is really into bitcoin.