I did not see that someone wanted to make "liseuse" the only term to be used for ebook reading devices in all languages. So where is the problem?
In my opinion it sounds nice, maybe not if pronounced leesoose
. And it's a wrong or right as ebook (isn't that the thing I read using my ebook reading device? after all I do not call my mp3 player "sound" either), ebook reader (someone who reads ebooks or maybe the device used to read audiobooks?) or any of the other synonyms currently in use.
As mentioned before this is just my opinion and I don't mind if someone thinks differently.