I guess technically they should have labeled Standby as Manual mode.
In the past, I have always cleated the tiller down to keep the boat basically on course so I could attend to things up front. (although I often sail with the tiller cleated just for convenience) The main thought is to assist when raising or lowering the sails. There have been times in the past when I have been in the middle of lowering the sails, and have had to run back and make a course correction and then run back up front to finish the job. This is particularly an issue when heading in, because that section of the lake gets crowded around quitting time. As soon as you start your motor, you loose your right of way. You can start out with an open path but it fills up, as the power boats speed past you to put in for the night. That is where I could see putting it into standby, and then bumping the tiller position to make a long sweeping curve in, rather than changing course a bunch of times. it just gives me more time to stay up at the front of the boat, taking stuff down. When I have had someone at the tiller, I usually have the sails in the cabin by the time I make my final approach to the marina.
Going into the marina is usually down wind, but usually by evening, the wind has died down enough to lower the sails while motoring down wind. There is still be some load, so as the sails come down, the boat directions changes. I assume that is where I would want it in auto, but once the sails are not catching air, then standby would be useful to make a large sweeping curve into the marina, while I'm still securing things.
BTW: IF I fall off, I can always hit the buttons on the wireless remote and have the boat come get me
But seriously, every time I go up front, I always have my life jacket on. The usable area of the lake is only about 600 acres, so the shore is always pretty close by. The weighted center board would probably anchor the boat before it ever ran into the shore, as the lake is very shallow.
Kind of excited about getting this thing, as it was sold cheap as non-working for parts. As it turned out, it was a very minor electrical connection issue, so I really didn't even need to dive into the circuitry.