I see no one mentioned Mega man Xtreme 2.
Yes, is true. I would understand that most people will forget about this game. No, it doesn't add any additional features when played on GBA like the zelda oracle games "Advance Shop" or Shantae's "Tinkerbat Transformation." But people also forget that the other feature of putting these games on a gameboy advance. It doesn't have "Enhanced" on the box, but extra unlockable content isn't the only feature of enhanced gameplay. These games altered color pallet to be brighter so it can be seen better, which indeed Mega Man Xtreme 2 does have just like the three aforementioned games.
While Ideally, I bet that it may not be prefered to use the GBA color pallet vs the original GBC ones for these games. But is worth noticing that all FOUR of these games had CAPCOM involved with them. Capcom published Shantae on Gameboy Color, They also was credited for both zelda oracle games, and they made Mega Man Xtreme 2, I'm surprised no one mentioned this either. Sounds like something to consider right?