I think the RnR is less forgiving to a dancer than the Charleston. If something isn't right, whether training time, injury, or imo relative sizes of the partners, there's nowhere to hide in an R&R. In the Charleston you can do panto like Chris or, like the injured Ali, classic moves such as the cross-legs, that don't require so much bouncing about.
That N&V would have issues with the lifts and drops was obvious before the start. I also think Natalie Lowe's acrobatics slowed the flow of their dance, because she always came down so carefully from those great heights to save her knees and ankles.
In this choice of dances, Charleston is the "Ballroom" and rock n roll the "Latin".