Ownership of a digital asset comes down to control of a private key rather than a name on an account record. That single fact separates crypto custody from every arrangement people are used to with money.
A key is authority, not evidence
A blockchain records balances against addresses, and an address can only be spent from by whoever can produce the matching cryptographic signature. The key that produces that signature is the whole of the entitlement.
There is no register of intended owners sitting behind the ledger. If a key is copied, the copy carries identical authority, and the network has no way to distinguish the original holder from anyone else.
This is why the loss of a key is treated as final. The asset still exists on the ledger and is visible to everyone, but no process exists to reassign it.
Self-custody moves the whole burden to the holder
Holding your own keys removes any dependence on a company remaining solvent, honest or operational. Nobody can freeze the balance, and no account terms sit between the holder and the asset.
The cost is that every operational risk transfers as well. Backups, device failure, malware, inheritance and simple human error all become the holder's problem, with no help desk behind them.
Hardware devices and split-key arrangements reduce single points of failure by requiring multiple approvals or keeping the key off any internet-connected machine. They reduce the risk without changing who ultimately carries it.
Custodians reintroduce the intermediary
A custodial platform holds keys on behalf of many customers and tracks individual entitlements in its own internal ledger. What the customer holds is a claim on the platform rather than a position on the blockchain.
That arrangement brings back familiar conveniences, including password resets, account recovery and human support. It also brings back counterparty risk in a form that is often underestimated.
If the platform fails, customers become creditors, and how their claims rank depends on how assets were segregated and which jurisdiction's insolvency rules apply. Those details vary considerably and change over time.
Insurance and segregation are not the same protection
Deposit protection schemes for bank accounts cover the depositor if the institution fails, up to a defined limit. Custodial crypto balances generally sit outside those schemes, whatever the platform's marketing suggests.
Private insurance policies held by custodians usually cover specific perils such as theft from cold storage, not a decline in asset value or the platform's own collapse.
Segregation of client assets, where it genuinely exists, tends to matter more than an insurance headline, because it determines whether the assets are part of the failed company's estate at all.