Certainly, as it should be.
>Do you choose a slightly gray text color which improves the overall appearance of the text but reduces the contrast
No, you do not. Good example.
>Do you include images?
Including images does not make the site inaccessible. Bad example.
>Can you express more of the visual identity by removing an image and including a web font instead?
We're talking about the primary textual content of the site. Not a header, or a menu item, or a title. Very few people are crazy enough to render the entire text of their site as an image.