As a sailboat enthusiast kedging is most often used as in the case of poor Blackbeard when you get caught up on something and need to move a small bit in a direction that’s against the wind or water. So usually just trying to get unstuck when you’ve run afoul of hidden sand bars or the tide shift leaves you in an awkward spot. You also might do it to help set an extra anchor if you’re worried about drifting on the tides.

Even deep water boats only have a few hundred feet of anchor rode and line and it takes a while and is a hassle to kedge out with your dinghy.

I have never in all my years of boating seen anyone do it as a method of general propulsion outside of just handling lines at the dock. It’s just sometimes your best shot.