My use case scenario for the iPhone 5, iPad mini and iPad 4 (or call it my justification):
iPhone 5 - makes calls, quick response to emails, music. I have a 32 GB as my music collection grows and while I appreciate having it all at my fingertips with iTunes match, I store some natively on my phone for the rare occasions I'm without internet connection.
iPad mini - this is the everyday, go everywhere device. Gonna grab an LTE 32 GB model so I can surf, read, play games, facetime anywhere.
iPad 4 - again 32 GB, this is my media device. Movies/Videos, more processor heavy apps, photo editing, document creation, presentation driver - my laptop if you will (I haven't owned a laptop since I got my first iPad - the 1st gen handed down from my dad).
Do I need all of these devices? Of course not. I'd say (and others agree) I use my iPad more than most people. I've had all 4 iterations and have carried them with me wherever I've gone. Done everything from watch the Avengers on a plane to create relatively complex spreadsheets and my resume. Not a day goes by I'm not using it for something - but like many have said I see there being specific uses for each device. Spreading the content across all three means less space on each (and cheaper replacements if need be) and a device with more specialized use. But iCloud allows everything I own on all 3 devices to be accessible on any at any time. My home iMac serves as my base station - I can remote in for more CPU intensive tasks but my iPad has served me well over the years.
I don't know why it's such an issue for some of you that people think like this - some people see the value/need and go for it. Others don't. To each his own. I worked at Best Buy for a little bit and had a guy buy 5 iPad 2s (at the time, the best) just to run his home's entertainment system (which I assume is something to behold). People do/find value in their own ways - my wife has to have a different $300 purse for different occasions. And the times we can afford it (generally as gifts for Christmas/Birthday) I acquiesce. Same goes for tech for some of us.
And that concludes the wall.
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The idiocy of assuming someone with both isn't also giving to others is a symptom of a huge problem in America. The jealousy/class warfare will tear our nation apart.
My dad drives a $100,000 car - would I ever buy one? Heck no. My Hyundai is perfectly fine. But he can do that because he's worked the better part of 45 years making something of himself (starting out living on dirt floors with 6 siblings).
By the way - he also gives more to charities and causes HE believes in than I hope to make in a year at this point. He's one of the most generous people I know.
Some can do both.