The lack of an option to preview the output quality is THE main reason I'm still using Photoshop today.
I bought Affinity Photo because I love many features of it.
Not being able to judge the image quality before saving renders the whole app allmost useless for me.
A lot of my work is internet related.
Getting the best compression / quality ratio is essential in this field.
Especially since screens with high pixel density are pretty much mainstream.