Charlie Scamp's approach was that of the Traveller brother I described, a rejection of any form of traditional approach, changing what was being communicated by the song.
His sister, on the other hand, sang much nearer to a traditional style and, in my opinion, maintained the feel for the content of the song far more successfully

Then I would say that you were nit-picking between the way Phoebe Smith and Charlie Scamp sang. I would say that Phoebe had the better voice but that you would be hard-pressed to satisfactorily distinguish differences in idiom, style and approach between the two siblings and to regard one as showing "a rejection of any form of traditional approach" and the other being "much nearer to a traditional style" does not accord with the recorded evidence. If you cannot recognise Charlie's intense involvement with his songs and admire the way he unfolds his stories then you are missing a worthwhile experience.

her tradition was dead and had long ceased to develop
You cannot consider changes in the vibrancy of a tradition without considering changes of its function aligned with societal change. The tradition evolves to survive or it doesn't. Matters of personal taste come into it in a big way. 'Like' or 'Dislike' are probably more important factors in attracting new participants to traditional song, dance, story-telling etc. than 'right way' or 'wrong way' pronounced by an expert however eminent.