Great question @naiad. The goal with this method/trick is to apply all modifiers on multiple objects. It’s definitely an unintuitive “easter egg” technique (of which there are many in Blender). Without it we would have to apply all modifiers in the desired order for each object individually.
In this specific case there’s only one modifier but it’s still saving us from having to apply that one modifier on each object.
***I’ve been teaching Blender long enough to know that I could be missing a hidden option somewhere that does this more intuitively. If anyone knows better ( @spikeyxxx ) please enlighten us!