It's not a big deal, but to me, this is a bit more handy to use than the triangle one. If this thing could be an option, it would be a great addition to those who prefer it over other color picking methods.
Again, if I could, I would not want to choose between having a circle hue picker and a square S-L picker. Currently you can only have one, but not both, and that's why I post the request in the first place.
I can't speak for the OP, but the main reason I'm not keen on the colour wheel is that the middle (triangle) spins around.
I would prefer the centre to remain in the same position regardless of hue so I know instantly what's what without thinking. Having it constantly spin round offers me no benefits, it just annoys me. Therefore the triangle would be OK if it had an option to remain static in one place so that the bottom left corner was always black, the top left corner was always white and the right corner was always full saturation. (The current triangle would need to be flipped for this, as black would currently be at the top in the below position).
Static Triangle:
As it is I use Boxes in Affinity Photo rather than the colour wheel as it stays static and therefore it's easier for me to think about. Bottom left corner is black, top left corner is white. Up increases lightness, down reduces lightness, right increases saturation, left decreases saturation. As the OP has pointed out though, picking opposite hues is easier with a colour wheel.
Boxes:
The square I think most people are familiar with though is not the one used in Boxes, but the one below from Clip Studio Paint and Photoshop, where the bottom left corner is black, top left corner is white and the top right corner is full saturation.
Clip Studio Paint:
It comes down to personal preference at the end of the day.
Not sure if you are aware but we have now added a toggle for Windows Ink in Preferences > Tools. Disabling this will return the app to the previous functionality.
