What is the downside of removing cataracts?

Sometimes. Can have more light sensitivity, get glare and halo, need reading glasses with a monofocal lens set for distance. The small risks associated with cataract surgery such as infection, bleeding, corneal or retinal swelling, dropped lens pieces, failed cornea in some situations, etc.
Not much. Cataract surgery is very rewarding for the patient and surgeon - i enjoy it immensely. Of course, with any procedure there are potential side effects and complications but these are usually small compared with the visual benefits. This is an exciting time!
No real down side. Not all cataracts require surgery. If best vision is worse than 20/40 or glare is significantly affecting VA, most surgeons prefer to do surgery sooner but depends on pt's sx, risk factors, preferences; also, though no guarantees with any surgery, many patients are less dependent on or free of glasses after surgery; clear lens removal also possible in some pts; more info: eyedoc2020.blogspot.com.