The Other tab covers a few features that don't fit elsewhere.
When Deeplinking is enabled, clicking on a filter will update the URL of the page. For example, clicking on a tag will indicate in the URL that this particular tag was selected: https://bootstrapped.ventures/wp-ultimate-post-grid/deep-linking/#deep-linking+post_tag:travel
The end result is that people can copy that link and share it with others. They will then end up looking at the exact same grid.
When you have filters for your grid, it's possible that selecting a certain combination of filters doesn't actually have any results in your grid. The optional text you set here will show up when that happens.