When I was looking at Disqus I had to logout/in to post from a different account. With WordPress native comments all I have to do is put in a different email/url and it's on a different profile.

I do like that you can see comments from many sites with Disqus though.

We actually do offer guest commenting functionality by default. You can continue commenting similarly as you do on native WP sites by simply not logging in to an account when posting a comment.