For me, this needs to be addressed on two levels - investing in something (typically like paying for college) - here I would tell the child about it at the right time (generally when it would be relevant), how it came about, and that they should start doing it slowly too, that it will pay off in the long run (and by paying for college, directly induce a sense of usefulness). Here I would vote for the MSCI all world.

If it is then a portfolio to pass on and "enjoy it", I would be more picky and opt for more dynamic investments, with the understanding that I will pass it on to the child at 18 with the knowledge if they are mentally mature for it at that time, otherwise only when they enter the workforce and experience the first difficulties in life (as a kind of hey, I understand that your generation has it harder than ours, so dad thought of it...).

I'm expecting it in about two/three years, but this will be one of the easier things with kids :).

Unfortunately, I was quite disappointed with the cost of the port. They lure you in with low fees and then don't let you buy a specific ETF, but depending on the strategy you choose, they put together about 6 funds, where it comes out to about 1.6%pa

Great way of education I think, teaching a child from a young age things about finance and the world of investments, thumbs up for me, I will definitely practice something similar and let compound interest play for their benefit.

When I have kids, I'll definitely consider investing for them. The best option for me is DCA into ETFs as you write + I would set up some stock portfolio with bulechips stocks for them.

I really like the gift of some stock. In the future, I might want to motivate my children this way too. If they see that they have their money in it, I would expect them to be interested in it.