The Remote Play technology uses a downscaled version of the 1080p image on the Vita screen, which only offers a max resolution of 960x544. The image is sent via Wi-Fi to the Vita, which sends the controller inputs which are decoded by the PS4. Basically, it is another use of the OnLive streaming technology, but because of the high bandwidth, it offers much better performance and more options that you can’t get streaming from the cloud.
Truth is, we don’t know how interested gamers will be in this; but for gaming around the house and if you already have a Vita, this will be a great way to use it. For developers, it is something more that they have to take into consideration in their design. Apparently, Sony is providing much of the code bits required to make this work, so really it isn’t that bad for developers; but the games have to be written with this in mind.
See it for yourself right here as Shuhei Yoshida speaks on Twitter.