Say you don't want other people to see/edit the customer database. You can set a password. When you open the application, it will instantly ask for the password. You don't need to quit the application when you leave your computer! Just go to the file menu and click on Block Access. Also, you don't need to protect the application with a password if you don't want to!
Say there are many customers on your database. Simply type the customer's name on the search field and it will instantly find the customer you're looking for.
You can also export and import the database, that way you will never lose any data. Having a backup of the database is always recommended.
There are many fields for you to enter the customers data. There's a field for just about any kind of information you may need to store.
All this and much more!