The Asus uses the new AUO 1440p 165hz panel, and the Gigabyte uses an Innolux panel. Both are very good panels, and the hardware features on both are comparable.
The only important difference is the Gigabyte has a notably wider color space, likely since it's using 10-bit (8-bit+FRC) while the Asus is only 8-bit. Not a huge difference, but would be noticeable to a trained/conditioned eye and the wider space may come into play with HDR (although incidentally, HDR 400 doesn't really mean much at all). Also, contrast looks to be a bit better in the Giga. All things being equal, I'd probably take the Gigabyte. The only detraction I see is it has that god-awful lighting on the back (how much money was wasted on engineering that gaudy embarrassment?

). Just me, but I wouldn't be caught dead with something like that on my desk. I suppose you could just cover the lights with electrical tape.
Yes, both of them state they come with a DP Cable, I'd be enormously surprised if they didn't.