One of the bedrock principles of academia is not taking credit for another’s work. The way that faculty enforce that directive is by requiring citations in student research.
But formal citations, whether in APA or another format, are used almost exclusively in academic publications. Nearly all other forms of communication use other methods to cite sources. For instance, if I want to credit the source of an idea in a lecture, I just say the originator’s name, as in “Albert Einstein said . . .” I don’t give a full citation midsentence.