It all has to do with the gluten content
the more you work dough, the more you develope gluten which is good for breads and such but not so much for any kind of quick bread like biscuits, muffins, etc. But it is protein content that matters. Bread flour is around 12-13%, all purpose 12-11%, soft wheat/pastry/cookie flour 9-10%, and cake 8-9%.
If I didn't have White Lily (and yes I do buy it specifically for making biscuits), I would use regular all purpose or a pastry flour if you can find that but I don't think I would go to a cake flour as I don't think it will have enough gluten. Or mix them. It just makes a more tender biscuit.
We used Martha White, White Lily and Southern Biscuit brands. If anyone wants any to just see what the real difference is, let me know and I'll ship you some.