Does it? I'm seeing RGB(0,0,0) for body text in my browsers inspector. Lighter shades are used for other elements though.

Be careful when using both (or going too far with either). I see many sites where the contrast between the text and its background make them uncomfortable for me to read, and my eyes are fairly OK so people with vision problems probably find such sites impossible.

If you want a commercial incentive to not do this: I just hit the "read mode" button or similar, and that strips your adverts as well as recolouring and enlarging the text, and if that doesn't improve things enough the same content is often available on another site a quick google away...