What does Milorganite do to weeds?

What specific effects does Milorganite have on weeds? Is it a herbicide that kills them outright, or does it work in a different way? Does it prevent weeds from growing in the first place, or is it more of a maintenance product? How does its effectiveness compare to other weed control products on the market? Are there any specific types of weeds that Milorganite is more or less effective against? And finally, what are the potential advantages and disadvantages of using Milorganite for weed control?