That's a narrow range. f/2? Really? On an UWA? Why? I'd be happy with a 16-24/2.8. Just my $.02
It's targeting people who work in really low-light (street/night) where the difference between f/2 and f/2.8 is whether the milky way shows up, or whether they get motion blur. Not really sure the point of a zoom, I think an 18mm f/2 would be a nice split. And obviously when you don't need to shoot at f/2, it would sharpen up nicely at f/5.6-8
But a 16-24 f/2.8 lens appeals to a different user base than 16-20 f/2. I can get primes in the f/2.8 range that wide for much cheaper than a 16-24 f/2.8 would cost. I cant get primes/zooms wider than 20mm that go <f/2, and I can't get a good prime/zoom wider than 24mm that goes below f/2.8. There's definitely a market there for it.
This could also technically be targeted at videographers, as it becomes a different focal length with all the video crop factors, and the depth of field is important. But I'm guessing that's not the main market for it.