I see 'art' as the marriage of ideas and craft. For me, great art is the result of exceptional individual talent, and a mastery of craft, which includes technical processes. It's having that control which allows the idea to be realised to its most optimum form. That isn't to say that technical flaws (perhaps beyond the artist's control) should necessarily preclude a piece of work from being considered art, and indeed exploitation of flaws can sometimes enhance the artwork. Certainly, when I view photography from many decades ago, I view it in the context of the technology used not being as good as it is now, so a lack of sharpness, or distortion etc, is of no significance. Many iconic images of war have been blurred, out of focus, poorly exposed etc, but we accept that because the situation is far from ideal for taking 'perfect' images. But for my own work, I want to know that if I'm making the effort, the equipment won't let me down. We all have our own preferences and choices.
I'd just like to say that although the 14-30 is my 'worst' lens, that's in direct comparison to my other lenses. The 14-30 is by no means a bad lens; on the contrary, it's an excellent lens. It's optical flaws are not significant enough to prevent me from enjoying using it. In fact, stopped down to f8, it's actually far better than I'd expected; significantly better than a previous 3rd part UWA zoom I'd used. I've never owned or used a 14-24mm lens, so I have no comparison. But it is a lot more expensive, and much larger and heavier. None of the reviews I read/watched suggested it was 'worth' the extra outlay for my own requirements. So we make compromises based on our own requirements and budget. I've used the 14-30 professionally, and had great results from it.
I use filters as protection for lens front elements, because a £40 or whatever filter is cheaper and easier to replace/repair than a £1000+ lens. I had an 82mm thin filter that I'd used on my previous UWA zoom, so I just whacked that straight on. My filters do tend to get scratched and battered over time, that's just the nature of how I work, so the ability to use a protective filter was a big selling point for me for the 14-30.