This will permanently delete your blog including all your posts. You can create another blog at this address using the Google Account you're currently logged in with, however, we can't restore your posts once you choose to delete your blog.
It's so easy to delete a Blogger blog: the delete button is easily accessible from the settings page and there's only one confirmation dialog. After you delete the blog, all the posts and comments disappear, but the blog's address instantly becomes available.
If you want delete a Gmail account, it's much more complicated. Google asks your password and it doesn't delete the account instantly. What's more, the address can't be reused and you won't be able to retrieve your messages.
For Google, deleting a blog is infinitely less important than deleting an email address, even though they're both ways to communicate with someone. Deleting a blog has many more side-effects for a bigger audience: broken links, broken hearts, less relevant search results, an entire context that disappears.