I would not say wind
steering is unreliable at all. You can rely on it to follow the wind, though, and I think that's possibly what you were getting at. It is true one would have to adjust it to keep it on course, but the effort was not onerous, it was all part of what one does on watch.
From 1985 or 6 till 2003, all our offshore
passages were with a windvane
steering. It was of home made construction.
However, in 1983, our little electric
tiller pilot stopped working and was not reparable, and we were three days north of Hawaii
on the way to the States.
Jim rigged sheet-to-tiller steering, which we used for the rest of the journey, using many blocks and surgical tubing he had brought "just in case," and I"m here to say that although not perfect by any means, it sure beats the hell out of hand steering 24/7, no matter what watch schedule you're on.
I think it would depend a lot on the sailing characteristics of the sailboat whether or not sheet-to-tiller would work well. I can imagine a full keel
"traditional" boat doing really well on an off the wind passage
with it. Many people who did that, also ran twin headsails downwind. Not at all sure how it would do on the beam (our boat required a lot of fiddling when the wind was on the beam). Said boat would also probably sail to windward pretty well with the helm
lashed. Our boat had a fin keel, and we never had a chance to try it off the wind, so really cannot comment on that.
The deal is that although electronic steering is precise, everything electronic on a boat is complicated, and is subject to failure.
If you start out from the get-go with a sheet-to-tiller plan, or a home made windvane, you can have more beer
at the end of the voyage, more shekels in your trousers, plus losing the need to feed the steering system electricity all the time. I think there's definitely a place for it, even if only as backup in case of a "what if?"