To be clear:
It looks like you're referencing a specific ROM hack or mislabeled version from the mid-2000s scene: . 1986 - pokemon emerald (u) (aka trashman emerald)
If Pokémon Ruby and Sapphire were the ambitious, somewhat messy first draft of the GBA era, Pokémon Emerald is the polished masterclass. It stands as one of the few "third versions" in the franchise that doesn't just add a few bells and whistles, but fundamentally improves the core experience, fixes the narrative pacing, and offers the best Battle Facility in the series' history. To be clear: It looks like you're referencing
The most significant upgrade in Emerald is the narrative. In Ruby and Sapphire, you fought one evil team (Team Magma or Team Aqua) while the other played the misunderstood hero. It was lopsided. Emerald smartly pits both teams against each other, forcing the player into the middle of a three-way war. The most significant upgrade in Emerald is the narrative
The "Trashman Emerald" ROM has become the gold standard for several reasons: