This follows from the “out of sight, out of mind” principle: no one will remember something they can’t see right in front of their face, especially since we rely heavily on our senses for interaction with the world; hence, why sight-based triggers work so well. We can’t easily remember what we can’t see (unless it’s a feature someone so thoroughly overuses, they remember as a result of developing a habit through sheer force of repetition), so it is frustrating to look for something that we only need occasionally.