Does removing overqualified elements really improve performance?

I used some tools to validate my css for improving performance and i got feedback asking me to remove overqualified elements.

It does makes sense as it can improve selector performance, but was surprised to see this one as overqualified:

"div#container is overqualified, just use #container"

Does this really matter? I have lot of such occurrences in my css and was skeptical if this can do any good for improving performance.