instructive

Conveying knowledge, information or instruction.

Well, that was an instructive lesson.

Some commentators have suggested that the activity represented by WallStreetBets and Trumpism are part of the same populist, anti-elite phenomenon, but if Trumpism in general is instructive at all here, it’s as a reminder that self-described anti-elite movements can, in fact, turn out to be much more complicated than that.

A case in the Finnish and Estonian languages. It expresses the means or the instrument used to perform an action.