Opening a crypto wallet for my kids?

I’ve been thinking about the best way to set my kids up for the future, and honestly, a traditional savings account feels like it's going nowhere with current interest rates. I’m considering opening a separate wallet for them and throwing in a set amount every month, mostly BTC and ETH, maybe some SOL, and just letting it sit there until they turn 18. It feels like a better "long-term play" than a piggy bank, but I'm also worried about the volatility when they actually need the money.

Has anyone here actually done this? I’m curious if you guys use a cold wallet and hide it away, or if you’ve set up some kind of custodial account. Also, how do you handle the conversation with them once they’re old enough to realize they have a "portfolio"? I’d love to hear some success stories or even "don’t do what I did" warnings before I commit to this.