>>56034870I think it's cool that this specific piece came from so early in Gen 2's production that it's actually depicting the beta Ruins of Alph - note the tower with the dome and the waterfall coming out of it to the left behind Ethan/Gold is the same building seen in the middle of pic related.
It also gives you a visual hint to try using your Pokegear at the ruins, meaning the radio signal thing is also something that was planned from the start and may have actually done something.