A 2-year-old doesn't NEED an iPad, but I was really surprised what a kid can do with it.
My dd had access to lots of screens since very young from being around relatives (and everyone owns an iPad AND iPhone/other smartphone), and she learned the whole alphabet and numbers by herself around 18 months old, not to mention being proficient at using everyone's ipad/phone. She figured out how to play music and videos, use youtube, take photos, adjust volume, use all the kids apps, etc. even faster than us adults. I mean, 'delete', 'charging', 'loading' were part of her vocabulary before she turned 2.
That said, I do think these electronics are detrimental to her concentration, and somehow I think they make her irritable, so I limit them when we're at home.