I sail both lakes and tidal waters, and yes, a trolling motor works about the same whether you are one or three people on board. I've used a 40# one for quite a number of years and recently upgraded to an EP-Carry (see
reviews elsewhere on this forum). My view on having a motor is that I explicitly don't plan on "self-rescuing". That is, as long as there's wind, I plan to sail my way out of situations, instead of thinking of a motor as some "beam me out of here" device. Having made that decision, I'm suddenly much more realistic about conditions I might attempt sail in, and careful to check forecasts to make sure conditions stay manageable. (I started with zero training and zero experience in sailing something the size of a DS, so it's not that I would have been able to count on superior knowledge or skills, at least not in the early days).
Now, I will plan on using the motor if there's a chance I'll hit a calm spot, and to navigate some stretches under bridges etc. where sailing isn't an option. In may case, the range required for the latter is < 1nm.
Now, I have been on a DS in an expedition style event over a couple hundred miles. We carried a propane outboard to be able to cover extended distances in some unspecified emergency. Turns out, we used it three times in a week. To leave the marina on the first day, to approach the dock the same evening (although I would have been more comfortable sailing up to it, frankly, and the third time, it refused to start. Having a stash of the propane cartridges was nice for morning coffee, though.
That last time, we ended up using a long rope to haul the boat around to a different location and then I sailed us out of the marina.
Incidentally, I had a tough time adjusting to the kind of motor where you have to turn it 180 degrees to get reverse. So used to having reverse power on the trolling motor. That's why I would have done better just sailing up to that dock.
Lesson for me: practice boat handling, how to do a U-turn in a small space, how to short-tack, how to not stall your foils, and how to gauge the stopping distance after you head into the wind. After that, you'll need the motor only where regulations or traffic get in the way.
However, while I continue to be happy with my choice, I readily concede that it's a matter of location, circumstances, and conditions. I can count on protected to semi-protected areas where some shore or island can be reached quickly if necessary (and across, rather than against the tide, if that matters). If I know an area will be becalmed for some time, but not all day, I'm content to take a nap, waiting for the wind to return. That's not everybody's thing.