It is much to do with the shoe you are wearing.
In martial arts and self defense training:
Front kick - The standard tennis shoe is a little more effective than a hardened bare foot using the ball or heel of the foot. A working boot/shoe is greatly more effective with the ball/toe, mildly more effective on the heel. A hard heeled shoe/boot is more effective with the ball/toe and greatly more effective with (obviously) the heel.
Roundhouse kick - Using the ball of the foot, tennis shoes offer a 'tearing' factor over a bare foot. Using the top of the foot, which we teach Only for sparring, a covered foot is going to hurt the kicker less and should be more effective considering the laces, eyes & hooks that many shoes have.
Side kicks were not mentioned in the OP but I think definitely fall under SA when wearing shoes and needing to kick. Extremely effective and practical kicks.
This seems like well versed material that is usually covered in most programs, especially those that use kicks as heavy offensive tools.