I have a MacBook air and an iPhone 6 plus. I'm perfectly happy doing things on my iPhone like web browsing. However, everyone on these forums talks about their iPads as if they were a nessacary and integral part of their computing set up. I'm an iOS developer so I do have an iPad, but I just feel like it has no use for me.
What do you use you iPad for that you can't/wont do on an iPhone pr laptop?
The problem is that most people are like you and think an iPad is a laptop.
Not everyone is an iOS developer. Some people do all their photo editing on iPad. Can you do that on a Macbook? Sure, but some people prefer the iPad.
Browsing the internet. It is better on iPad. My phone is 5.2", about the same size as your iPhone 6 Plus and browsing the internet on a phone and on a tablet are 2 totally different things.
Other people do, for instance, vector illustrations,
Other people, unlike you, don't want to carry a giant iPhone in their pockets.
Different devices for different uses.
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I used to use my iPad all the time when I first got it 2+ yrs ago. Now, I find I barely use it, and, when I do, it's just for occasional web browsing. Now that I have the iPhone 6+, I am using it even less and thinking of selling it.
That's because your phone is new and you're using it more. As time goes by your 5.5" screen will get smaller and smaller to your eyes.