>>55368222I think that's the most logical interpretation of most modern shiny locks, all the returning legendaries in SV being shiny+size locked is probably just cause they didn't want to deal with the hassle of the model randomly changing size or colour at an arbitrary point, now that there's no seperation between the overworld and the battles.
The other reason being that shiny locked pokemon can now also be used as bait for engagement in online competitions or other promotions - I know a lot of people who didn't give a shit about the SWSH online battle challenges until they started handing out the shiny Galarian birds, and i'm willing to bet they'll do the same with the shiny Ruinous Treasures or the Loyal Three at some point down the line.
>>55369394The mechanics of the Dynamax Lair falls into the "don't let the player hold up progressing the story" category, except in this case it's "don't let the player hold up other people", because if you could immediately see the shiny in Dynamax Adventures, there would absolutely be sweaty tryhard hunters who would force-quit and abandon the raid as soon as they saw the non-shiny legendary, which would screw over everyone else just trying to beat the raid.