Why can Event Tokens not be traded for Chests?

My understanding of the Key/Chest system is that keys are from honor and chests are from succeeding on a variety of champions.

Why then, can only keys be bought using event tokens? Is this not offering a work around for the players who struggle with the honor system while leaving the honorable players behind, to sit on a cache of keys even while maxed on their 4 monthly chests?