A blindfold is a tool that can be used to achieve temporary blindness. Using a blindfold is a good idea if you are about to encounter a monster that can do you harm with its gaze (floating eye, Medusa) or that can blind you (yellow light).
After gaining an intrinsic telepathy by eating a floating eye corpse, applying a blindfold is good for detecting monsters, such as that leprechaun who stole your money or those soldier ants you want to avoid. It's also a good way to defend yourself from the gaze attack of pyrolisks.
However, a towel is more useful than a blindfold since it also gives temporary blindness when needed and it has other uses, too.
The blindfolding was performed by binding a piece of the yellowish linen whereof those of the Amahagger who condescended to wear anything in particular made their dresses tightly round the eyes. This linen I afterwards discovered was taken from the tombs, and was not, as I had first supposed, of native manufacture. The bandage was then knotted at the back of the head, and finally brought down again and the ends bound under the chin to prevent its slipping. Ustane was, by the way, also blindfolded, I do not know why, unless it was from fear that she should impart the secrets of the route to us. [ She, by H. Rider Haggard ]