An editor and I were discussing alt texts because of this edit he made using VE. In the edit, he described that all he was able to do was blank the alt text in the VE image editing form.
Because of that, that left the images with blank alt texts, which leads to the undesirable situation that these would be treated as decorative images. That means they were not accessible.
Obviously the preferred end solution would be to leave an appropriate alt text, but he didn't know what that was in context, and I suspect many editors do not either until faced with discussion that talks about alt texts. (Maybe not many users set an alt text, I don't know.)
I think VE should either a) delete |alt= when that form becomes blank by actions performed in that form, or b) allow editors to delete the parameter a la the template parameter indicator. Given it's marketed to less experienced users, and deleterious effect if left blank (which is unlike most templates), I'd tend toward supporting a). While alt text can be noisy, and occasionally the default alt text is really noisy, that's better than vanishing the image for the users who need the alt text.