Google has been down on expandable memory for more than a little while now. Nexus devices abandoned micro SD cards several generations ago. It's been the biggest downside to buying one of Google's own brand Android devices.
Things will be changing for the better when Android M arrives. The latest revision of Android will now automatically encrypt an inserted memory card and format it as a logical extension of the internal storage.
It's better than nothing I suppose, but it does present some future issues. Like being unable to swap memory cards between devices, data loss if your device faiIs and reliance on the cloud for all your future device backups.
Fortunately other OEMs have retained micro SD card shots on their Android devices so it's possible to retain some of the benefits of expandable storage without having to wait for Android M.