I'll echo what many have said in that you don't "need" rudder at this stage. However, if you plan on staying in the hobby and advancing, its a good idea to "grow up" using rudder and start getting used to it as soon as you're comfortable, so that it becomes second nature to you. I've seen some pilots that never got used to rudder, and it gets to be obvious. When you first learn to fly, your mind is going a million miles a minute, so it can be overwhelming to deal with all that in the beginning. But after you can take your plane up and breathe, you might as well start using it in turns and such. In some models, as you said, it doesn't seem like it does a whole lot. But in others, especially precision, aerobatic and 3D aircraft, the effect from the rudder is much more pronounced.
The good thing is, when flying, as you experiment with rudder to get used to it (you give too much or wrong direction) its probably the most forgiving of control surfaces for errors. I feel it can only help to have it...worst case scenario is you don't touch it. But at least its there if you want to use it. And if you are ever going to fly anything beyond basic circles and occasional loops and rolls that you don't really care what they look like, learning the rudder is inevitable. As was mentioned, aerobatics and 3D will certainly rely heavily on rudder skills. Good luck to you.