Very good advice. In fact in some cases where larger fish are involved, fishermen will put a good sized polyform ball at the end of their anchor line. When a good fish hooks up, and they need to chase it, they just release the anchor line, fight, and hopefully land the fish, then return to their buoy, tie up to the anchor, and set the fishing lines out again.
You never know when you may have to release a hung anchor in rough weather, or some other circumstance. With the buoy, you'll be able to come back to it another time and free it up.