Hmm... personally I think it is a mix of good choice in music and the interpretation of it
at precise moments, while it's a different discipline just look at the Shib sibs' Fix You program- that song is so overplayed in general, but the timed their elements perfectly to rally the crowd to get involved, same with Hanyu's final step sequence in Romeo and Juliet back in 2011 (and of course, the final minute of V/T's Waltz, or just, well, any v/t program lmao). You need a lot of power at certain points if you're going to go down the route of choosing a well known song that requires such standards. Which is why D/R don't do much for me on that front because they just rely a little too much of the emotion of the music in itself if that makes sense? I found that in the final moments of their LP the strings in the song are beautiful, I want to be involved and drawn in by it- but just for me their movements don't
quite get there enough. The changing notes on the strings could be matched by arm movements, or they could have timed the throw at another point perhaps in order to place the preparation time they needed for it a little bit better (I don't claim to be an chorographer by
any stretch of the imagination oh gosh, but I have worked for years with how to time sound and visual media together).
In contrast look at V/T's Violin Muse, outside of the lifts during changing and long notes, they match them whether it be a change in posture or a movement of the hand, and a quite... incredible thing I noticed (which im not actually sure was done on purpose

) was even their foot positions as they skated, the literal basic movement of skating round the corner in preparation for one of the final lifts was timed note-perfect. When you want to work with music that requires that subtle interpretation, the smallest details at certain moments is what you need in order to draw the audience in.