Vision could be misled, in special circumstances. The other does not. In one ladder, the dividing bar between the two moves up as the ladder tumbles you may be able to discern if you look carefully. And so we see, as Robin's arrow sinks slowly in the west, that perspective provides many relationships. Perspective factors are used by vision.
Many factors are available.
Vision does not use all of them. One such is the cross-ratio, it seems. See K. Niall's oncoming work for the best answer to date.