Ereader

Think I mentioned it somewhere here before, but it's usually to keep costs down. eInk devices are relatively less demanding than modern smartphones, and utilize some older chipsets as they don't need the extra power. This also helps keep costs down.

Problem with using holder chipsets is that Android itself only supports a few generations at a time, so they won't be able to get the latest versions of Android, nor the privacy and security features that come with it.