Slow sailing is a Junior skill and an important one. The objective of slow sailing is to get to a fixed point in space (a dock, a man-overboard,
a buoy) with zero speed. The idea is to come in on a close reach course, where you have an accelerator and a brake.
With the mainsheet all the way out, the sail is depowered, and the brake is the wind and sea against the boat. Pulling in the mainsheet on the falls is the accelerator. You line yourself up on a close reach
course and sail to the target.
There are two skills involved:
1) lining yourself up on a close reach course to the target, and
2) slow sailing on that course to it.
Let's talk about hitting a buoy at zero speed, as it's the hardest of the maneuvers. When you dock, you usually have some room for error, as you don't have to get to a precise point on the dock. But wait, what about a busy Saturday where you have to thread the needle between the only two boats where there's any space between them to dock? If you can lightly touch a buoy on a slow-sail, you can do precision docking.