And then there is the storage problem. A food mill is an awkward piece of equipment to store. Nothing can sit in it, and it can't sit in any other equipment. By it very nature, it is meant to sit on top with a handle that sticks out. Whereas a ricer can lay on its side in a corner of the cabinet. And unless it is made with delicate material, you can even place other equipment on top of it.
I used my food mill (that I just had to have) once and then got rid of it. Whereas I still have my ricer and use it frequently.
When I scoop out the potato for twice baked, I put the flesh through the ricer. It makes the fluffiest potatoes even with additions of chives, cheese, sour cream, etc. Your choice. And you find that you use less milk.