From a single seed phrase, BIP85 can be used to derive seed phrases to "child" wallets. You can use these child wallets in different contexts (ex. mobile hot wallet, starter wallet for spouse/mom/dad/whoever). If the seed phrases to a derived child wallet were compromised, the original seed phrase would still be secure.

Instead of needing to maintain and backup multiple seeds for different wallets, you can back up one seed phrase that gives you access to multiple derived wallets