Long story short, shooting at ƒ5.6, the image is probably far more important than what lens it was taken with. Buy the lens you like, regardless of why you like it, or even if you can't even figure it out. But that, still leaves, buying fast lens for it's speed...
IN most cases, attributes other than sharpness, or zoom vs prime, make a lens desirable, even price doesn't make as much difference as we've been led to believe, for the amateur. Have no doubt that that 35-80 won't hold up to day in day out use, if you're a pro photographer, but for guys like myself, I'm sure it will last my lifetime. It's great you can add cheap light lenses like these without sacrificing much when you use them. They take as good pictures as you can set up for them.
this image taken with the DA 35 at ƒ4, nice clean crisp auto-focus and still plenty sharp, you'd never try this with a 4.5 zoom if you had the 35 2.4 available.
And there will always be low light situations that are beyond zoom capability. FA 50 1.7, at ƒ2, hand held. That DA 50 ƒ1.8 gives you a lot more than a DA*50-135 at 50mm... at 1/12 the cost, but more than stop faster.