IS is useful for taking pictures of non-moving objects, at slower shutter speeds, especially at longer telephoto distances. You don't always have time to set up a tripod, or don't want to lug a tripod with you.


That's not marketing. It's not making up for poor skills. It's necessary optics for a specific set of conditions. If you find yourself in those conditions often (chasing birds, bugs, kids, candid shots, all in low light, or with long telephoto lenses) then buy yourself some IS lenses.