The answer to this is complicated and I'm not going to try to cover all the angles of it, so I'll simplify the answer with this: it depends on what you value and what you're willing to pay a premium for; if you care deeply about the optimal ratio of commodity functionality versus price, then the iPhone 5s (or most any Apple product) is probably not for you. That is NOT meant to be a snobbish, classist, elitist jab and I mean that respectfully.
In a similar vein, yes you could do similar things on a $500 Lenovo laptop compared to a $3000 Retina Macbook Pro; driving a Tata Nano or Honda Civic will get you to your destination just as fast (within reason) as a nicer car. Buying the cheapest food possible will get you calories just like more expensive food... the list goes on and on with other things (clothes, coffee/tea/wine, jewelry, etc).
So ask yourself: what did Apple value when they designed and manufactured the iPhone 5s, which are different than the values used to produce competing products? If those values are similar to your values, then it's worth every penny.
