If you want to setup Gmail on the iPad so you could access Gmail when you are away from my desktop or on the road. Benefits over the generic Gmail set are as follows; your iPad will now store Drafts and Sent Mail in Gmail instead of storing them locally on the Device. That way if you access Gmail from your desktop or iPhone your drafts and trash will be accessible on that device. This method will also work with the iPhone.
Gmail includes excellent spam protection, phishing warnings and virus scanning; ultimate organization, conversation view, POP3 and IMAP access and currently 8 GB of inbox storage that continues to grow every day.