Sherry's previous words had suddenly made Ybur realize that a shapeshifter's "Variable Mind" was actually an ability well worth developing.
Because shapeshifters themselves do not master spells.
When it comes to spells, the first thing that comes to mind for most people is "rubbing their hands to conjure a big fireball and blasting away," but destruction is not actually the strength of spells. There are far too many means to achieve destruction. The real advantage of spells lies in their wildly imaginative variety of special effects: rending space, mastering time, material transformations, reversing cause and effect, manipulating fate, creating things out of thin air, mental control... These unimaginable feats are where the power of spells truly lies.
Fortunately, shapeshifters can also obtain the innate "spell-like" ability of their Mimicry Object through their own Variable Mind ability.