I think people buy zooms for convenience, and they can be practically a necessity for certain types of pro photogs like those who do events. I think zooms tend to be a compromise between aperture and a range of focal lengths. There are of course very excellent zooms like your two 2.8 zooms, but I'd always prefer the fast aperture of a prime. I think having a lens that goes open to 2, 1.4, or 1.2 even offers much more flexibility for someone like me who doesn't need to "make the shot" to put food on my table. As a hobbyist, I'd pretty much stick with primes. Just my 2 cents.
I can see a UWA zoom like in your sig to be OK since most of the time your at F8 anyway.