sure, but it's very inconvenient to keep wealth personally. i'd have to keep gold in my house or something. it's too complicated for most people.
not your keys, not your coins. centralized custodial services always have the possibility of failure
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that's what Bitcoin fixes. I no longer need to keep gold in my house. I can keep my Bitcoin in cold storage on a device smaller than a wristwatch. no trust in a centralized custodian required.