If I'm setting up a base at mushroom island, getting some chickens, sheep, goats, pigs, and villagers there to set up the necessary farms is a royal pain, because I can only transport one animal at a time in my boat, forcing me to make multiple trips to the mainland. Villagers are even more of a pain in the ass, requiring elaborate minecart systems to transport them even short distances, and breaking a whole in the nether roof for longer distances.

It would be so much easier if I could just use a silk touch enchanted axe to kill them, and get their spawn egg. Then, I could transport all the mobs I needed all at once.