I feel that as long as the time-delay is long enough, the eye movement decreases frustration more than difficulty. For example, I spent 10 minutes (and I could have spent much longer) looking for the scroll in the teacher“s house before I noticed Link“s eyes.
I can“t remember how many times I“ve solved a large puzzle several times over but not completed it because I missed a small part of it. Imagine trying to light a whole lot of torches: you run from the start to the finish, and by the time you get to the finish you presume the reason nothing“s happening is because the earlier torches have gone out, but the fact is you“ve missed one all along. That“s the sort of thing that Link“s eyes can tell you. What they can“t tell you is why you need to light the torches, or when you need to to turn the dungeon upside down, or how you need to defeat phantom gannon etc.