No it is not for your benefit... and it doesn't do anything to avoid the possibility of fraud. The reason that they do this is so they can sell you (as a supposedly real person) to advertisers.
Anyone can have multiple facebook accounts. All you have to do is create more than one email address. It is very easy to manage multiple email accounts, you just forward your new email address into your real email address.
This is a stupid restriction that is easy to work around.