A lot of independent authors find that there isn't a book description on their Kindle page, sometimes for several weeks after the book is listed. They then write a review and put the book info there. The big controversy is: how many stars would you give your own work (well, five, of course, if _I_ wrote it) and how many should you (5 gets you included in more searches and if the author only thinks it's average, why bother reading it?).
Most of these authors then remove their own review once the book info gets listed (but some don't).
I guess it isn't much worse than the ones where you can tell the reviews are by the author's family, best friends, those who owe him money or are paid shills. Better, actually, if the author is up front that the "review" is only to add the book description