Google is trying to get some traffic back from the file-sharing services:
Have you ever tried to attach a file to an email only to find out it’s too large to send? Now with Drive, you can insert files up to 10GB – 400 times larger than what you can send as a traditional attachment. Also, because you’re sending a file stored in the cloud, all your recipients will have access to the same, most-up-to-date version.
Although Google is late to the game, their implementation feels like just right.