I understand that <meta charset="utf-8"> declares the character encoding of the document to be UTF-8.
According to the HTML specs <meta charset="utf-8"> is not mandatory and the only allowed charset for HTML5 is UTF-8 anyways. So leaving it out does not hold back any useful information in an HTML5 document.
Regardless of whether a character encoding declaration is present or not, the actual character encoding used to encode the document must be UTF-8.
However, almost every resource on HTML5 urges to use the tag despite it being redundant and unnecessary with regards to the specs.
Is there any reason to use it?