To create a follow up to track comments just select "Email follow-up comments to email@example.com".
It is also possible to track blogger comments through rss/atom feeds but not many people like to read the comments as feed items.
Unlike WordPress plugin "Subscribe to Comments" where anyone can subscribe to email notifications, blogger allows only Google/Blogger account readers to subscribe.
So only readers who have Blogger/Google account can be benefited by this new feature.
Hope soon Google will allow everyone to subscribe to comments.