so on the GTS I've been putting up pokemon holding their evolution items needed to evolve, and requesting the evolution itself (eg. seadra holding dragon scale for kingdra, electabuzz holding electirizer for electivire). surprisingly every single one I've done has been taken really fast which is great to complete the dex.

my question is, why. what do these people gain from it? are they just being nice or are they semi-casual players looking to swap for a good nature or something?