Browsers store their credentials in predictable places that make them easy targets for malware. There is account syncing hazard from using browser profiles. Even if you don’t sync your passwords, a hacker who gains access to primary email accounts can change the passwords of secondary accounts created by the primary account. For example, using Gmail for your bank account and recovery account to reset forgotten passwords.

To make browser manager password manager more secure, use master password and Two-Factor Authentication. Browser master password are usually localized, which only works against physical access to your device. Recommended for shared devices.

Reputable third-party password managers have better security.