Microsoft recently launched the Nokia 215, a $30 basic phone with 2g internet and Facebook/Messenger. This is a genius short term play. There are billions of people who can benefit from this phone but would not find a smartphone compelling.
Imagine for a moment that you live in a village in Kenya. Smartphones have two key downsides. They're expensive, which makes them targets for theft and damage. And they have terrible battery life. 1 or 2 days compared to the 29 days that the 215 and other basic phones can last. This is critically important when you only have access to electricity once a week when a truck comes by with batteries.
However, you might still want a smartphone. The killer smartphone app is is messaging. Not search, not the web, but messaging. Messaging is important because it allows you to contact friends, businesses, and family. Sending a message on WhatsApp is somewhere around 1/30th the price of sending that same message over SMS. Cheap enough to potentially make a smartphone worth it despite their downsides.
This is where the Nokia 215 comes in. If you and your friends use Facebook Messenger user then this phone has everything you need. Tremendous battery life, highly inexpensive, and built in Messenger. Quartz is incredibly pessimistic, but I would not write this phone off just yet. It might just be a home run.