That's true, but that's true of everything. Not every microbe can survive in every environment, and the number of microbes that survive is really what determines contamination. If you start off with one, it could take years before it reaches a noticeable level. If you start with a few billion, then it could be a few days. When you do a through clean, you're ensuring that you can reach your expected storage time by eliminating as many microbes as you can.
But in the end, if they don't hurt you plants and your plants are getting the fertilizer they need, how much does it really matter?
I appreciate yts, you know what you're gonna get. I can be sure to have a movie ready to go for the family in 15 minutes.
Really, the benefit is the audio will be stereo and dialogue will be either heard or not at all and I know there's nothing I can do about it.