The first part of your statement is true however this typeface is used during a different phase of the design process. It even reads as such in the headline ("wireframes"). That'd be like suggesting mock responses are counterproductive because a large part of building an application is in dealing with live data. Sure, once your interfaces are hardened then you can worry about handling live data but there is a time when all you're going to worry about is handling the response. Similarly, there is a time in the design life cycle where a higher level, "does this work" is valuable.
It's an appropriate tool for a part of the design process.
You are right, this can be useful during initial stages of the design process. Counterproductive was a poor choice of word, let me better elaborate my concern. I assume the use for this typeface is to present wireframes to the client, free of "distracting lorem ipsum". I think showing clients any web design that lacks a typographical direction is an omission of the majority of the design in most all scenarios [1] and not fit as a representation for the future of that design. My personal design philosophy for the web is to accommodate the other aspects of the design to the typography, not to fit the typography secondary to the balance created by the preexisting design.
It's an appropriate tool for a part of the design process.