for me its not really to prevent them, but rather to make them more rare, i really like the idea cause it could create a niche, say if you need alot of materials to make the forges and there would be no restrictions, meaning that a person or a guild might use all of his time on forging that one special material and other people could buy it from him,
automated timesink vs a cooldown, point of automated time sink being you have to log back in and collect it rather than get it instantly, making people value what they craft a bit more, especially if we have no crafting professions.