Erasing your device prevents others from seeing your content. If you choose to erase:
Google may not be able to completely erase all memory cards on your device
Find your phone and Android Device Manager can no longer locate, ring, or lock your phone
You’ll permanently lose access to all info on your device that wasn’t recently backed up to Google
Your phone will be erased the next time it’s online. If it doesn’t come online again, it won’t be erased.