From Wikipedia, a mail exchanger record (MX record) is a "type of resource record in the Domain Name System that specifies a mail server responsible for accepting email messages on behalf of a recipient's domain, and a preference value used to prioritize mail delivery if multiple mail servers are available".

Why do you need to configure your MX Records for Google Apps?

You'll need to set this if you want to use Google Apps for Work - Gmail for your organisation. By adding the MX records it'll allow the systems to direct and associate your mail to your specific domain.

If you have a website, or you see information has been deleted from a webpage, but still shows in Google Search results, you can ask Google to update or remove the page.

This is a pretty cool feature that I just discovered, so I am highlighting this in case you didn't know there was such a feature available.

This is great for me right now, as I recently just changed my subdomain name and need to make sure people are not hitting blank pages. From an SEO perspective, this is very important if you have pages that you may have deleted permanently so that you can let Google know before it plays a factor in your website ranking.