Working with additional Hard Drives in Linux

Background: CentOS 7.1 on Azure.

Step by Step on how to add additional storage: https://azure.microsoft.com/en-us/documentation/articles/virtual-machines-linux-how-to-attach-disk/#how-to-initialize-a-new-data-disk-in-linux

Question here is – why should I create a new partition within the drive as oppose to simply formatting the drive with ext4 and mount it that way?

I was able to test it and mount the drive to a newly created folder /data and it seems to be work correctly.

Can anyone share the pros and cons on why one should create a new partition within the drive?