Why do fine artists buy and use only paint that is in the art stores?
It is good to try it but but it’s really a pain in the butt to make one’s own paint .It is not cheaper,does not save time and you will not wind up with a superior product.Not to mention finding suitable containers to store it in and the hazards of dealing with toxic pigments in powdered form .I would much rather spend that time painting.However priming one’s own surfaces can be very useful.