Zoan fruits having minds of their own would explain how some inanimate objects can eat a devil fruit and given sentience.
Also, why some Zoans users acted a bit different upon obtaining the fruit. Kaku's obsession with Giraffes upon eating his Zoan could be passed off as a quirk, but maybe he was influenced a bit by his fruit. And in other cases, it's a more harmonious melding, like with Lucci and his carnivorous Zoan going well with his bloodthirsty nature, or now with Luffy and his Nika fruit.
I wonder how much of Kaido's current behaviour is a result of his Zoan fruit's influence.