Feature or Bug? WP Review custom fields

When creating a post that is not a review, all of the review custom fields are added to that post even though “No review” is selected.

If a post is set to “No review”, shouldn’t those fields be ignored, and not be set when that post is saved/published? Is there a reason why the plugin does this?

Just seems to be a waste of DB space to set those fields in posts where they would not be used.