Nasal polyp removal absolutely necessary?

Depends: If you have a nasal polyp on one side - yes it should be removed to make sure it is nothing more serious. Polyps almost always affect both nasal/sinus cavities. If it is seen on only one side - it should be biopsied (or removed). Polyps do not "need to be removed." indications for removal would be 1) if having surgery for chronic sinusitis 2) breathing difficulty 3) trouble smelling.

Not always: If nasal polyps are small, do not cause significant symptoms and do not invade local structures, like the eye socket and area around the brain then they do not have to be removed.

Depends: Even though nasal polyposis is almost always a benign inflammation arising from the lateral wall of the nose, the need for surgery depends on your quality of life. If you can not breath and can not smell and steroids orally on and off have not helped, then surgery will be most gratifying. However, the presence of polyps in the absence of symptoms can be treated medically.