Is the 'getPropertyValue' method required for retrieving CSS?

Question

Could you tell me why we need to use the getPropertyValue method if we can use only the getComputedStyle one?

For example, this will work,

Answer 1

I believe it is for properties that can't be dot-notationed, like background-position. Though I suppose that brings up the question "why not use brackets notation, i.e. getComputedStyle(element, null)['background-position']?". It's possible they just wanted a getter method for the class (CSSStyleDeclaration).