Mira in Xenoblade X works like a big puzzle without actually being one (at least not being an obvious one), you only can reach certain locations once you progress in the game, indigens are there to prevent you go any furher, so there's a sense on progression and reward when you finally reach that impossible place you though never would get by leveling up equiping better sets, discovering new sight sites can be pretty challenging because the complexity of the game world. So once you practically can't reach any new place on foot there comes the Skell, it was actually pretty clever give this out later in the game (license thing), because otherwise the challenge of reaching place on foot would be pointless; overall everything every place, every cave, every unreachable point, every sea, every enemy was designed with player progression in mind, think Metroid power-ups to get to new areas, except it was masterfull implemented in XCX that you problably never felt like it was aparent.