Sitecore works best for storing users and custom user profile properties for a user. It works based on .Net Security Mechanism. Custom profile properties are very much useful when you need to store information of a user which you need to be available throughout the system. It can be accessed anytime. No need for doing database transactions for the values which are stored as a custom property for a user. It can be used to store values for a user like Full Name, Birthdate, Gender, etc.
