为什么Wordpress中的注释ID是连续的（唯一的）？

I notice that in WP blogs the comments order by continuous id (id=203, id=204 and so..). while I understand the class names "parent" "child" - to sort the reply to thread, I didn't figure out why the id's are continuous - maybe to choose hide/show specific comments?I notice that in WP blogs the comments order by