1. Again, a good tool makes things easier, not harder.
2. Google 'Photoshop Alternative' and Affinity Photo makes 9/10 'alternative lists'. Whether you agree or not, Affinity Photo is considered an alternative to Photoshop, and the folks at Serif are doing nothing to contradict that. You can't look at Photoshop and Affinity Photo side by side and proclaim with seriousness that the latter isn't trying to replicate the former.
3. It doesn't matter whether you think my workflow is destructive or not. If I need to achieve something and my 'destructive workflow' gets me to that goal 5 times faster than the alternative, then why on earth would I take a longer and more difficult route instead?
4. Smaller budget. Yeah, I think they could have squeezed it in since this thread started in 2017. Not expecting, nor wanting Adobe bloat level updates. Just basic stuff - which others have noted - is found in free alternatives.
Bottom line is that there are two serious contenders to Photoshop; Gimp and Affinity Photo. But for some reason Affinity Photo is having an identity crisis about what it wants to be, and for even more explicable and strange reasons, Affinity Photo fans are working overtime to reject suggestions for alternative workflows, which wouldn't take away anything they already have and love, but instead add features that would draw a larger crowd.
I wonder why that is...A simple crop selection feature won't take ANYTHING away from your workflow. Why are you so opposed to me adding it to mine? How is adding this feature going to hurt you?