I love those stylistic traits too! Plus it makes since with the hair for on models their hair is actually too fluffy for their hats so Nintendo has to resort to making it a morph-
64 Mario has a more elongated cap to compensate for his hair which is pretty neat.
oh because their hair "realistically" doesn't fit in their hats? I always thought just that their hair just gets pushed down, but never enough to stick out their hats. Nintendo did this in Super Mario Odyssey, simply pushed down the cowlicks (yay I get to use that term again) and the flips when a hat is on Mario's head.