Hmm, yeah that makes sense.
But the shiny star can be seen while interacting, shouldn’t be mega
bubble be seen too? Don’t get me wrong, I’m all for that better
flow. But those two icons (the star and bubble) usually show up
together, like, both show up in the storage boxes, in trades,
offers, etc.
The shiny star is shown because that information is loaded anyway
for the main image of the Pokemon.
The mega-able state of the Pokemon has no direct influence on its
image, therefore that information is not needed and not loaded (for
performance reasons, yes)