This kind of construction is very common in English, like chairman, ice-cream, horseshoe, fairy tales, bus stop, and so on. Pretty intuitive. It is a kind of compound noun as in English. In Chinese, it is free to construct new words in this way.
There are some more examples.
中華人民共和國 = 中華 / 人民 / 共和國 (Three nouns)
香港鐵路博物館 = 香港 / 鐵路 / 博物館 (Three nouns)
全國人民代表大會 = 全國 ／人民 / 代表 / 大會 (Four nouns)
The reason behind your question on "nouns as adjectives" is just because you try to fit English grammar in Chinese languages. This is not necessary. When a pupil studies English in school, teachers teach much stuff on the part of speech and its morphology, and the way to judge a sentence is grammatically correct. Morphology is unimportant in Chinese languages. If you pick some Chinese dictionaries, the part of speech is not always mentioned. Chinese feels natural to word meaning and order, conversation and passage context.
In Chinese tradition, it is advised to write as few words as possible. 的 is mostly optional but it sometimes enhances rhyme and rhythm, and acts as a pause in speech ,and functions as a word boundary in sentence. Some writers immersing too much in Western morphology might overuse it.