What do you think of putting graphene OS on this and using it as a cold wallet?
Is it still better to go with a coldcard?
Discussion
both coldcard and Google have proprietary hardware / proprietary secure element.
I don't recommend either of those options if you are serious about safeguarding your Bitcoin.
What would you recommend?
anything that is fully open source hardware that you can use with your software wallet of choice. Trezor Model T with Sparrow Wallet interface connected to your own Full Node is a great option. Before anyone talks about the physical access hack, yes you should always use a passphrase with any wallet. Basics 101 lol
For Mobile, use Sentinel to read your Xpub from Sparrow and connect your Full Node using Samourai DoJo.
Anyway this seems to be the "best" setup out there.
Thanks for getting back to me
but if you only have those two choices hypothetically, then going with the cold card is the better choice.
I'd go with a Coldcard and truly airgapped. It's cheaper too. If you already have an old phone that would be a good option. You'd want to run it in airplane mode and essentially never use it, making it a "warm" wallet.