The fingerprint (usually along with the full derivation path for that key, which provides complete key provenance information) only helps identify the key. origin of a specific key. However, this does not affect the resulting address.
- Software wallets are used to identify which signing device should be connected to sign with a specific key. You can also use it to correctly populate various PSBT fields that require primary source information.
- The signing device can then use the information in the PSBT to identify what the descriptor’s internal key is and what the derivation path is for the private key needed for derivation and signing.
Without key origin information from the PSBT, the signing device has no idea what its own key is, which key belongs to a co-signer, or what derivation path to sign with.
please refer to this Saving that information as part of a backup is not an option.: Even if you own the seed (root key) from which a particular xpub is derived, there is no guaranteed way to infer the derivation path of that xpub. This is required to use it. The only option is to brute-force attack all possible paths, which is usually not guaranteed to succeed or even feasible.
Of course, it is safer to remove the key origin information from the descriptor before removing it from the descriptor for third parties who only need to use it to generate addresses, such as watch-only wallets.