Why are exceptionally tall statues of the Buddha and Guanyin built?

When I read [this article on the tallest statues in the world](https://www.theatlantic.com/photo/2018/10/photos-15-tallest-statues-world/574531/) , I was struct by how many of them were of important Buddhist figures: of the fifteen tallest statues six are of Guanyin (Kannon/Avalokiteśvara), five of the Buddha, and one of Kṣitigarbha, for a total of twelve out of the top fifteen! Why are such tall statues built? What significance does the height of these statues have in the religious lives of Buddhist adherents? Or are these statues not built for true religious purposes, but as an unofficial competition between nations, just like they compete over the tallest skyscraper? Nine out of the fifteen were built in the 21th century. Who commissions these statues? Statues of this size would be beyond the budgets of most temples. See also: [this question on why precious metals are used for Buddhist statues](https://buddhism.stackexchange.com/q/1747/11169) .