well graphic design covers a wide range of possibility - everything put together is designed more or less, and if it's for art, it's a graphic

I've just switched over [from SAI2] to PS CC for drawing line art with the cintiq pro - if this is for animation then I can import it into Harmony which will vectorise it, and then I can colour it in that program - if it's not for animation it does not ususally need to be vector and I would PSD it into SAI2 and do the colouring there as it is a lot more straight forward to do flats/highlights/shades in that program; and then back to PS if it needs any plugin effects - if it did need to be vector I would use inkscape for vectorising the lineart [because you cannot export vector from Harmony]

I still use xara for vector asset when that is easier to put together in an external program, but to be honest this is tailing off

Personally I would prefer Illustrator CC to Affinity Designer, but unless the asset takes off again in a big way i could not justify the cost, xara designer is adequate as things stand for vectors - for raster affinity photo I really like a lot, but now i have PS I am unlikely to use it so much

as I said in a thread oh about 18 months ago, if you work with others and they use PS/Illy, then it is often cutting your nose off to spite your face if you dig in and refuse to sync for the sake of saving a few quid a month