If you can do it, you can sometimes use that skill to quickly compare whether two adjacent vertical images are identical. If they are, you will just see a single version of the image as normal. If they are different, you will easily see a ‘fuzzy’ part of the image that won’t resolve and stay still (hard to describe, it’s like when I try to read text in a dream).
A practical application I use now and then is when I want to compare two columns of data on a screen. Use the magic eye technique to overlap the columns and any differences will be immediately obvious, even with a lot of data.
The cartman inequality