kircubbin2000
Potatoes keep.No need for frozen.
So does flour, you could say there is no need to buy shop-made bread. It is useful to buy your bread readymade, though. I have a breadmaker, which kneads and bakes my bread twice a week, but I also buy part-baked rolls to freeze and use if I can't even put the ingredients into the pan and set it going. They cook in ten minutes and are crisp and fresh.
For some purposes, ready-prepared and frozen potatoes are very useful. I wouldn't buy frozen baked potatoes, but frozen mash and potato croquettes are at least as good as what I would make, so I always have them in my freezer.