But a seed phrase is a representation of a private key. You only need to know how many private keys can store a wallet, and that is what I am showing on "Multiple Private Keys" row. I don't have a Multiple Seed Phrases row.
Coldcard can store multiple private keys (or seed phrases) in the SeedVault.
I can generate a bunch of private keys that are derived from any seed phrase using open source websites like iancoleman.
So I really don't need hardware wallets doing that, because each address have it's own public and private key.
https://iancoleman.io/bip39/It's totally different thing to have multiple seed phrases on same device.
That means that I can import multiple backups and use multiple wallet accounts in the same time.