Smartness is based on education and effort, not on a stupid phone. There are people who don't even have phones and are smarter than iPhone users...Does the iPhone teach you math, biology, etc.? No? Well, then that just proves that iPhone users are the same as any other type of phone!
Apple has done such a good job branding, that people believe them. It is amazing when you think that a company that evaded paying millions of taxes, that has their expensive products produced by people paid very little and have a high rate of cancer due to the lithium, can convince consumers that they are being smart.
People that think smart people that use iPhones are smart is a misleading conception. Anyone can walk into a store and purchase an iPhone or any "smart"phone. Heck, you don't even have to buy a phone depending on who your carrier is and/or the type of contract you are under. Just look around; you can't walk down a major city block without seeing someone talking into their phones or texting someone. To sum it up: It's easily accessible.
People go back and forth with devices based more on cost and availability, rather than how smart they are. Android and iPhone are very comparable in the services they provide and there is no upper hand between them. If you think smarter people use iPhones, you could make the case that dumber people use them too.
I personally have an I Phone and its all about taste. If anything I would make the argument that one may be less intelligent for falling for advertising. I feel that more people use I Phones for brand recognition more than they want them for any features and advantages the phone offers.
Smarter people do not use iPhones, because there is nothing better about a smartphone than an Android. Smart Phones do the same things. iPhones just cost more, because you are paying for a known brand. People who use Androids are smarter to save their money, rather than pay for a status symbol.