Issue: edit blog comments

I just posted a new blog entry which only happens once evr blue moon.
Someone commented on it and for whatever reason I clicked on the edit button and to my surpise it worked.
I entered some text and hit send sure that an error would pop up and it didn't instead my edited comment was posted.
Is it intended that I can edit someone else's comment to my blog or is that a bug?
If it is intended then why???