I think the days of the conventional wind vane only, are nearly over, but for a few boats running very low on power and doing lots of miles. I know more and more boats especially those with wheels in the center of the cockpits, whom have removed the wheel and it sits near by, but out of the way, many others who never use the wheel. In my own case i probably manually steer on average 10 to 20%. I used to enjoy actually steering, holding a course anticipating the next puff, creeping upwind to get around that point. Now days I more enjoy setting the autopilot, and making small sail trim adjustments and adding or subtracting 1 or 2 degrees to the autopilot, often resulting in another 0.5 to 1knot and sundowners starting earlier. As soon as the anchor is up auto Pilot is on, if fact sometimes even before hand and a wind vain wont help with Set, wind variations, or if you want to creep upwind. Tacking in lay lines, or just ducking downstairs for a pee

I wouldn't be without, nor would I have vain.