Whilst at present TodoMVC provides a simplified baseline for comparing JavaScript MV* frameworks, we feel that this at least gives developers an opportunity to narrow down the list of them they wish to explore further. No one should be using TodoMVC as the be all and end all of which framework they use as there's significantly more to it than that. That would be a little silly :)
With respect to the comment lower down in the page regarding the nitty gritty not being covered (auth, validation, routing etc.), it's a valid point and we currently have plans for tackling this in version 1.1 of the project. Initially Backbone.js, Spine.js, Ember and CanJS will have complete end-to-end examples offered but we hope to expand upon this as we work our way through releases.
At the end of the day, our goal is to make it as easy as possible to find the framework (or frameworks) that best fit your needs and hopefully give you some incentive to investigate one or two in more depth before making your decision on what to use.