Regarding ColdKey, the project may look cool and satisfy some coiners' egos or whatever, but from the very beginning it was an idea based on trusting the creator, which is an instant no-no when it comes to Bitcoin. I personally would not trust my keys to anyone (not even my parents or siblings or GF/wife or whoever else). Not because I don't love them or trust them in the general sense. But it is a fact that all of us are human beings and are thus prone to mistakes and weaknesses, which can lead to compromising the security of whatever it is we want to protect.
When it comes to Bitcoin, you keep a low profile, NEVER reveal your keys to ANYONE, never advertise specific amounts or even ownership of any coins, never brag about how rich you are, and never compromise your OPSEC.
There's no need for ColdKeys. The best ColdKey is stored in our neurons, and should stay in there, and stay immaterial. Just like Bitcoin.
I agree with everything you've wrote, but I disagree if you wouldn't trust anyone with your keys because we're humans, we're not eternal in this world and we don't know when we left this world.
I don't think you would abandon all of your money you've make until right now, there's must be someone need to take over your Bitcoin and continue your journey to hold it.
At least your child need to know your keys, of course after they're matured, know about Bitcoin and already understand about money management.
If you die without giving the keys to anyone, the value of your stash will be distributed among all existing Bitcoiners...