So, you are thinking that it may be in your best interest to leave the decay in your mouth? I see cavities all the time that are so small that you cannot see them on an x-ray, but they "stick" whne you probe them in the mouth. When we go into te remove the decay, it is often more extensive than it appeared. If you wait til it hurts, you will need a root canal.
No way it will do more harm than good.
All fillings will leak ofter a period of time and need to be replaced. The ADA says the "life expectancy" of a resin filling is 5-7 years, but done well can last much longer.
There is no benefit to doing nothing.
Also, once you have the disease of caries (tooth decay) in your mouth, it spreads. Get it filled!