Not really sure what you're achieving by calling it either a smartphone, or mobile device in all honesty. Yes, it's a marketing ploy in many ways but so are many things we take for granted. I also think for the average consumer, the term smartphone helps them differentiate. I know many people who don't want a smartphone, they want a basic phone so avoid anything called a smartphone. It's simply a label to describe the handset, albeit slightly misleading. In fairness, to the end user they are smarter than they were twenty years ago. Siri is AI to some extent, people regard this as smarter. Automation = smarter to some people. 

I cannot see what is achieved, objectively, by calling it something else in this scenario. Nobody owns a monopoly on the term smartphone as opposed to some terms such as all vacuum cleaners being called 'Hoovers'.