BuddyPress.org

Actually, I just looked at the code, and the comment there is correct. The entire function is wrapped in a function_exists check, which means that you could simply put your own version of bp_dtheme_blog_comments() in your child theme’s functions.php, and it would override the one in bp-default (no changes to comments.php necessary). The way that you’ve done it will continue to work just fine, of course.