So, does this peer-reviewed article "count" and "matter" to prospective employers? The short answer is, yes, it counts, but not as much as a more focused article in the disciplines to which she is applying.
It counts in that it shows her prospective employers that she has the skills and experience of publishing in peer-reviewed journals- that helps them be more confident that she will be able to do so again. This is huge, as there is nothing worse than hiring a faculty member who just can't publish- it creates heartache for all (unless, it is at a teaching college where publications are not important).
However, it does not show subject matter expertise, which is something that will be important to do. Regina might wish to try to publish an article, since she is a interdisciplinary scholar, that bridges the two disciplines in which she will seek positions.
Of course, so much depends on the specific positions for which she is applying, the type of university (teaching verses research focus), and the nature of the units to which she is applying (i.e. are they going to value her eclectic interests).
Those with eclectic, interdisciplinary interests (as I am, with interests in masculinities, poetry as qualitative research, immigration, globalization, ect.), have to be very intentional about how they plan and execute their careers, and must have a great deal of mentorship and guidance. Without this, it is easy to fall between the cracks of ridged disciplinary boundaries in the world of academic hiring, and then tenure and promoting. Trying to work in many areas of interest at times leads to concerns with establishing a clear publication trajectory (and this is important at many universities).