Why? Because I love Kindles, silly!
I won't be writing a review of it because I'm lazy and tending to some tiny helpless people, but I will point you to my pal Jason Snell's Kindle Oasis review:
Yes, the $120 Paperwhite is the better buy. But the Kindle Oasis is a great splurge for people who simply want the best ebook reading experience around and don’t really mind that it costs twice as much as the step-down alternative.
He and I are very much of the same opinion about the Oasis (this one, and the previous version): they are fantastic but most people should just get the cheaper Paperwhite.