ebook reader, play games, apps to learn stuff (i.e. kids learning the alphabet or playing math games like Matific), use it for "portable TV" (you install Netflix, HBO, YT etc. where you can download the movies/series you want and you can travel with it and not use your phone's battery when on a plane/train), photo-frame (like the author did)(you can buy a cable that 'corners' and in a same-color-background you won't be seeing the cable).
Oh, and you can install Skype (or whatever) to talk to far-away-family, so you can make 'calls' (considering that calling a cellphone in an another country is cheaper with Skype).