But the verbosity is also one of its weaknesses for large projects; it adds a great deal of overhead in terms of keeping track of the tags, especially if the HTML needs to be re-arranged. And with no language-supplied rules for how much whitespace to use or where (beyond "all adjacent whitespace is compressed"), there is too much flexibility for a large team to work smoothly. My usage case doesn't mesh with your example, because I'm working in an environment with version control and multiple developers. The guy using Notepad will be told to get a tab-aware text editor, because his changes will mangle the whitespace in the file and lead to unnecessary noise when he commits.
When structure in your whitespace is already desired (to avoid making your version control noisy), you can leverage the fact that you are structuring the whitespace to make it a semantic element. This greatly decreases typing, makes the code easier to eye-scan, and allows details such as proper closing bracing to be left to the compilation tool and not to the developer. I agree with commenters who have noted that HAML has been proven useful for some developers.
I would categorize both SHPAML and HAML as tools that let you be more productive with HTML.