A POP3 e-mail account lets you send e-mails from one e-mail address to another.  This means you can set up an e-mail client to send and receive e-mails when the POP3 protocol is enabled.  POP3 was developed to help users with shoddy Internet connections to login to their e-mail.  Basically, you login to your e-mail using POP3, download the e-mail messages and attachments to your computer and that deletes them from the e-mail server.  From there, you use your e-mail client to read, respond or forward messages.

If you are using Gmail, you can enable your POP3 Gmail account to utilize a third party e-mail client, such as Outlook or Thunderbird. While you will have to enable support for your e-mail accounts via the clients, too; first, you must enable Gmail to allow you to login via POP3 support. In order to do this you want to login to your Gmail account and head to Mail Settings.

Once there, click on the Forwarding and POP tab. Forwarding e-mail simply lets you forward e-mails to another e-mail address. A POP3 Gmail account lets you download those e-mails. Scroll to the POP Download section and Enable POP for all mail. Once clicked, you can further customize how you interact with Gmail. Basically, you can decide if you want to keep copies of your e-mail on the server or not. Then, Gmail will walk you through the steps to set up your e-mail client of choice.

A POP3 Gmail account allows you to utilize a third party e-mail client.  Since these programs give you more control over your e-mail and how you store it, using them makes things easier on you.  You can send, receive and organize e-mails via a client and you can take advantage of any sort of organizational structure the programs will give you.  Taking advantage of POP3 will give you control over your e-mail.