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I can see how the style in the first video could be interpreted as trying to make things "bigger and badder", but what about the under 12 video? It strikes me that in the U12, the same lordosis that's seen in the first video is not being used for shaping, but rather just to ensure body contact. And yet, I can see how that would develop into the adult style in the first video if you got used to dancing that way.
I wonder to what extent the emphasis on body contact was a result of the coaching philosophies that became dominant in continental Europe. In the UK, there's more variety in the approaches at a young age. For example, here's a video at a UK juveniles competition - the first round, and at a younger age, so the standard is lower, but you can see the different approaches being used by different couples:
For example, among the stronger dancers in this heat, number 557 with the blue dress appears to be using the same technique for body contact as in Europe, but 349 with the red dress is using a different contact point completely - right front to right front instead of right front to center - and 573, also with a red dress, doesn't seem too concerned with maintaining constant body contact at all.
The right front to right front style is unusual, but has been used by high level dancers, such as Bob Burgess and Doreen Freeman in the 1950s, and later by Richard and Janet Gleave, based on the videos I've been able to find. Harry Smith-Hampshire, world champion in 1961, was a strong advocate of constant body contact in his Dance News columns, so presumably he used it himself; but, one could wonder if his retirement from back problems had something to do with that style, too.