Disqus said about it...
1. Your comment history and activity will only be viewable by you.
2. Existing users who are currently following your account will no longer be able see your activity via your profile or daily digest emails.
3. Disqus users will no longer be able to follow your account.
4. Existing followers will still show in your stats, but they will not be able to view your activity.
After them, Is there any SEO benefit, We can think about it?