be it a smartphone or a dumbphone, they're both referred to as mobile phone. and if you're always on the move (aka mobile) like most people are nowadays, having a smartphone (aka a mobile phone) is sine qua non for working people. you don't always have access to a desktop or a laptop computer. there are many people that use them not only for social media or whatsapp but also, and more than that, for business.
Many years ago, I looked forward to having a "pocket PC". As part of a "body LAN". With AR glasses, and virtual keyboard and mouse. But instead, we have these tracking devices that addict us to stupid social media. All for corporate greed and state surveillance.