I think it's a positive thing when movies can turn people on to folk/trad music. I share the concern, especially with Celtic music, that people might get a wrong impression, in thi case, that all Celtic music is new-agey, but I think people who are inspired by Riverdance and seek out more music will likely encounter the more traditional sounds if they keep looking. Even if movies and shows get some things wrong or only show one aspect of it, the fact that people are inspired by it means that there are many more chances they'll hear the "right" stuff eventually.

-chanteyranger