Nokia owns several HEVC patents, in fact I think they're currently suing apple about it. This is a veiled attempt to get everyone to use their patented tech so we can relive the mp3/mp4 clusterfuck. You would be a fool to use this for anything.
What's so bad about WebP? It's not the best thing in the universe but it beats JPEG and PNG and has a wide support base. With a shim it has native support in most browsers anyways since WebP is a just a single frame of video. And as a bonus you don't have to worry about someone suing you for royalties down the road.