This is particularly useful when making animated sprites for video games. For the Godot game engine (and I believe Unity) the Aseprite file importers use the tags to automatically set up animations allow you to play specific animations by code without have to do any in-engine setup.

Without tags you have to instead generate your own spritesheets and lay out the animations by hand in the game engine, and if your sprite sheet gets rearranged then you have to redo the animation setup.

Supporting Aseprite compatible tags would be a nice productivity boost for game developers, and would mean I no longer have a need to even open up Aseprite.