I assume you are talking about an electric rice cooker. I have one and use it regularly, but it probably isn't necessary (as a separate appliance) if you don't cook that much rice.
I used a microwave rice cooker for many years, plus a steamer that does rice, and of course I've done it in a regular pan. I like the electric rice cooker since I can put the rice and water in and forget about it until its done. Its a convenience.