Firstly, I haven't played Picto any great amount, most for doing open-world stuff like fates.
So I'm hoping there's an answer that's obvious to those who've played Picto a lot more.

Secondly, is there a formal word for an ability that turns into another ability under certain circumstances?
If so, that word should be used in the title instead.


To the actual question:

It seems that Picto cannot cast Muse without the related Motif being cast first, and likewise cannot cast Motif when the related Muse is available to cast.

So why is Motif and Muse not one button/ability?
Cast Mofit, it becomes Muse. Cast Muse it goes back to being Mofit.


Likewise, stacking White Paint allows the casting of Holy in White.
When only White Stacks exist, Holy in White can be cast while Comet in Black cannot be cast.
Subtractive Palette converts a White Paint into a Black Paint.
When a Black Paint exists, Holy in White cannot be cast but Comet in Black can be cast.

Since it's one or the other and they both draw from the same resource, why is this not one button/ability?
Gain a Black Paint, Holy in White becomes Comet in Black. Cast Comet in Black and it goes back to being Holy in White.


Cheers.