It's an unwelcome adulteration. Because a "folk song" ripped loose from the manner in which it was traditionally sung will finally lose whatever "folk" character it ever had. And I challenge the assumption that "generating interest" is somehow a good in itself, if it is done at the cost of destroying what gives the music its value. Bronson said it better than I ever could:

So many today are becoming aware of folk-song through the medium of stage, screen, radio or phonograph that it is well to insist again and again that most of what they hear is at least as far from genuine folk-singing as the broadsides are from traditional ballads. In strict truth, there is and can be no such thing as a professional folk-singer. A singer who has his livelihood to gain through that medium can never consider the song as an end He must attract and hold the attention of many people, and inevitably he must become aware of those particular aspects of his song and of his performance that arouse the liveliest and most immediate response in the majority of his listeners. Inevitably, he will come to emphasize these elements of repertory and of style: so that, the longer he sings, and the greater his success as an entertainer, the further from genuine folk-singing will be his performance. Of all deleterious influences on folk-song, the most corrosive and deadly is the consciousness of audience appeal

This is by no means to say that genuine folk-singers do not often bring to their singing a high degree of individuality. But this personal contribution is properly involuntary, inescapable , and below the level of conscious intention. It is an attribute of the song, as in their singing the song exists. A recent collector in Alabama, Byron Arnold, has significantly registered his impressions in this regard. "These songs," he writes, "were sung quietly, naturally, never dramatically, and entirely without the mannerisms and cliches of the concert soloist. It was as if each song, as I heard it, was a creation by the singer for the satisfaction of an inner compulsion. Here is a touchstone of genuineness for our native tradition.