...If you can't see the full address and the private key so you can verify that the private key is actually, for that address,
while making sure nobody else has seen / still has the private key then you no longer have BTC.
You have a lottery ticket that may or may not have
BTC in it when you finally scratch it off.
Look a handy thread that not enough people read:
https://bitcointalk.org/index.php?topic=3315347.0-Dave
Been saying this on and off for years. And with apologies to the coin / collectable makers that have not fucked everyone it's still a bad situation.
The coldkey was the last straw so to speak.
There are now enough electronic ways of generating private keys through provable secure hardware.
Get a bunch of opendimes
https://opendime.com/ or satscard
https://satscard.com/faq or one of the other similar devices out there and have them generate the address. Ship them with your custom coin. Make f--king sure people know that there is no private address on the coin.
You can laser laser etch, engrave it, make it pretty, or if you want use a sharpie to write the address on it, who cares. The ONLY way to get to the private key at that point is by using a device that WILL TELL YOU IF THE PRIVATE KEY IS OUT THERE.
It's even better since you can now DISPLAY the coin without fear of loosing the
BTC on it. Because you can keep the device with the private key on it elsewhere. Someone steals the coin, it sucks but you still have your
BTC.
And lets not forget, even if the maker is trustworthy security holograms can suck too:
https://bitcointalk.org/index.php?topic=5401502End of rant.
-Dave