An up-front comment: This answer has managed to attract a fair number of downvotes, as well as several very helpful follow-up comments (which have since been moved to chat). One hypothesis offered by a commenter for why so many have chosen to cast downvotes is that my answer maybe too focused on just one field (economics, which happens to be my field) while failing to explain what a habilitation is. Well, the question was not about what a habilitation is, was it? Instead, it was about how it's viewed in the US (and, presumably, Canada as well).
I've decided to shorten my answer drastically to make it focus on (a) what I believe are commonly held views among academics based in North America and (b) an explanation of why they are likely justified in holding these views.
I suppose any answer to your question will depend importantly on your field of study. My answer is informed by what I know is the state of affairs in my field, economics. However, I believe the views I state below are not limited to academics employed by North American economics departments.
Simply put, most academic economists based at North American universities have never heard of -- or are, at most, barely familiar with -- the concept of a "habilitation". To the extent that they think they know what it is, it's widely regarded as an awkward and even embarrassing device by which a person, after having earned a doctorate, enters an extended period of indentured servitude to some "big name professor", during which time the "habilitand" is supposed to acquire and demonstrate serious research skills and, ideally, manage to publish a couple of well-regarded papers in top-notch journals -- while also having to engage in such career-irrelevant activities as sprucing up the big-name-professor's lecture notes and fill in for the professor's lectures when the professor decide to be some place else.
To the extent that a European habilitation has any value at all in North American economics departments, the only thing that matters are the publications that (should) go along with the additional academic degree. The degree itself is pretty much irrelevant.
Is this state of ignorance willful and detrimental, or is it maybe entirely rational for these academics not to bother finding out a lot about what this habilitation thingy might be all about? I'd say it's the latter. In economics, there has been -- for many decades -- a huge difference in the perceived quality and status of a U.S. or Canadian Ph.D. degree in economics on the one hand and a (continental) European doctoral degree in economics on the other. (Aside: what matters, of course, is the thoroughness and breadth of learning and the research skills that come with the pursuit of the degree, not the nationality of the degree holder.)
Earning a Ph.D. degree from a high-quality North American graduate program was (and largely still is) seen as the vehicle that opens doors toward obtaining an assistant professorship at a selective university or college.
In contrast, most (all?) US econ department hiring committees know -- usually from painful first-hand experience -- that they needn't bother considering applications from persons whose main qualification is that they have just received a doctorate in economics from a European university. (Well, there have been some notable exceptions to this rule of thumb, in economics. However, they are the exceptions that prove rather than refute the rule.) If the European job applicant possesses both a doctorate and a habilitation, the only things that matter are the quality and quantity of the applicants' publications. (Well, the applicant's proficiency in English might matter a bit as well, if the position entails some teaching responsibilities...) If anything, the European doctorate/habilitation candidates might be at a disadvantage relative to the job candidates with "just" a Ph.D. from a North American institution, who often have one or two promising job market papers but no publications (yet) in top-notch journals.