How is it bothering them and are you sure it is a spaghetti worm?
There are a couple reasons why you would want them, the spaghetti worm that is:
1. They are good detritus consumers
2. They are a good indication of nutrients. Their population balance is related to the amount of food available.
3. Source of food for some creatures
Out of those three the main takeaway is that you can use their numbers or population as a visible gauge nutrient balance. Too much food and their population will explode. Not enough and it will decline. It is pretty quick and thus a nice visual sign.
Few drawbacks:
1. They are ugly
2. Population explosion - such that they will start to float around the water column