It's also considered a good way to knock out any coliform bacteria which might have seeped into the aquifer. We're sitting o top of the Snake River aquifer, one of the best in the country. My well has a static levezl of abouit 120 feet, and, with lots of dairy farms/feedlots around, you know the coliform is going to be a problem.
We tested our well when we got here in 2018 and found it positive for coliform (but not e. coli, which is a good thing). Our well people told us to pop off the well-head cover pour in a gallon of bleach, open all the hose-bibs and faucets and pump until things didn't smell like bleach anymore. We took a sample back to the lab and no coliform found. Now we do it every six months to avoid any re-infection.
EDIT: ... and we do have an RO unit, too; but I'd rather err on the side of caution!