You probably don't have kids, but I'll respond anyways. What if your kid already has real finger paints, musical instruments and all manor of "real world" toys and objects?

I recognized that my two children could use a touchscreen almost a year ago when they were 1 and 3 years old. When the iPad came out it was a no-brainer. Unlike a mouse, touchpad or keyboard, the touchscreen on my iPad is very usable (apps are a diff story) for my now 2 and 4 year olds and makes discovering computers a joy for them.

Yes they still go outside, get dirty and explore like any other kid. They just have this in addition to all that "real" stuff.