Yknow once you establish and get the hang of your rules for the character, it’s time to break them.
The standard style explains the head shape better for 3D while the toony style is just more freeing to draw more stretchy expressions with its nonrestrictive rules. Just go ham. These exercises is similar to how they say you should learn realistic anatomy first so stylization can be easier, yknow? Not that I follow that rule every time haha/