Forget wifi and 3G.... I know several dozen people who have no idea why anyone would buy an iPad in the first place
The bottom line is that we buy what we find useful whether it is or not.
My mobile phone is supplied by my employer. I can use it for personal use and they pay the whole bill each month... The downside is that they won't let me get a 'hotspot' type phone. They only pay for a voice/texting plan so I can't do any tethering.. But on the upside, my cell phone costs are zero dollars a year.
I got the iPad mainly for browsing while I'm on the road. My job often takes me out to the boonies where there are no WIFI spots.. I can't tether..... There's no WIFI... So, my iPad had to be a 3G model.
I didn't know when I bought the 3G model that there was a dedicated GPS unit built inside. This was a real bonus. If I draw out out my cupholder, the iPad sits right in the middle of the dash of my F150 truck. I downloaded the GPS Drive app and then gave the Magellan GPS unit I had to a relative.