All the websites can be accessed using single login credentials. So no need to remember login credentials for each web site.

Users can maintain his/ her information in a single location.

Passport authentication in ASP.NET refers to using external authentication providers like Google, Facebook, Twitter, etc., to authenticate users in your application. The advantages of Passport authentication include:

Simplified User Authentication: Passport authentication simplifies the authentication process by allowing users to log in using their existing accounts from other platforms. This reduces the need for users to create yet another username and password combination for your application.
Increased Security: Since users are authenticated through trusted third-party providers, Passport authentication can enhance the security of your application. It reduces the risks associated with managing user credentials and protects against common authentication-related vulnerabilities like password guessing, phishing, and brute force attacks.
Social Integration: Passport authentication allows users to log in using their social media accounts, which can lead to increased user engagement and a smoother user experience. Many users prefer the convenience of logging in with platforms they already use regularly.
Single Sign-On (SSO): Passport authentication supports single sign-on, enabling users to access multiple applications with a single set of credentials. This streamlines the user experience and eliminates the need for users to log in separately to each application.
Customizable Authentication Flow: Passport authentication provides flexibility in customizing the authentication flow to fit the specific needs of your application. You can choose which authentication providers to support and tailor the user experience accordingly.
Scalability: By leveraging external authentication providers, Passport authentication can improve the scalability of your application. It offloads the authentication process to third-party services, reducing the workload on your servers and enabling your application to handle more users concurrently.

Overall, Passport authentication offers a range of benefits including enhanced security, simplified user authentication, social integration, single sign-on capabilities, customization options, and improved scalability, making it a popular choice for ASP.NET developers seeking efficient and secure user authentication solutions.