As the name implies, a potato ricer is made to do just that. It turns a boiled potato into little rice-like pieces that can be stirred into silky smooth creamed potatoes, gnocchi, and many other dishes.
Do you have to have one? Certainly not! I’ve successfully cooked without a potato ricer for years.  Even though this model is about the smallest I’ve seen, it still takes up a lot of cabinet space. But, it’s inexpensive, fun, and it does do its job like no other piece of kitchen equipment, I’ll have to admit. So, if you have an extra $15.00 or so to spend and a place to store it, go for it. A potato ricer is worth that and more.