The colon has no singular use
Krahn 14 [Albert Edward Krahn, doctorate in linguistics from the University of Wisconsin-Milwaukee, May 1, 2014, “A New Paradigm for Punctuation”, //zrubin]
To find a coherent assessment of the use of the colon is difficult, suggesting that, although it has several “technical” uses (such as introducing lists of items or preparing the reader to focus on something), a sole or best use of the colon otherwise seems nonexistent. Some uses fall into general categories like problem/solution, question/answer, statement/explanation, generalization/details, and similar dualities. On the other hand, perhaps this is the second role of the colon after all: to visibly reveal arguments that have two parts, one on each side of the symbol. But there is no easy linguistic description for these two roles, the technical uses and the more meaningful pairing; that may have to wait for more research.