Sounds like some people don't know how simple and almost invisible the Companion pets were in D3. They zipped around picking up gold, that's it. They were tiny and were barely visible. They did nothing else.
It's not like Torchlight where the pets had an inventory, items could be equipped, give them spells to use, they contributed in combat, abilities that upgraded their power, you could send them to town to sell for you, feed them fish to turn them into a more powerful creature for awhile and I'm sure other things I'm forgetting. You could have them loot for you, but you had to click on what you wanted them to loot, so there was limited control.
As pets were in D3, they won't be missed.