It may be that notation has a renewed utility by virtue of creating a copyrightable artifact.
That's simply not true. In the US choreographic works have been explicitly copyrightable since 1976, and things like the Balanchine Trust have existed for over 40 years. Written notation is not necessary - a video is sufficient.
What organizations like the Choreographer's Guild do is more change the cultural expectations around dance copyright than the legal possibilities. That is, in the dance/entertainment world, often times a choreographer is hired for peanuts and is simply unaware of their legal rights around copyright. But when it comes to what is legally possible/necessary, there is no difference really between what, say, a photographer who is hired to do a photoshoot can do vs. a choreographer hired to produce a work of dance.
I found this interesting article about a very well-known choreographer and his quest to copyright his works, including his famous "Single Ladies" choreography for Beyonce: https://www.billboard.com/music/music-news/jaquel-knight-bey.... The thing I find weird/ironic about this is that the Single Ladies choreography famously copies a lot from Bob Fosse's "Mexican Breakfast" (the article I linked talks about this in detail). While I personally agree with the quote from the article, "You see the three ladies, you see the inspiration — but the funk, the stylized movement, they’re extremely different. I mean, how I got here as an artist is being inspired by those who came before me", in terms of copyright law, I think there is much more similarity between Mexican Breakfast and Single Ladies than there is between, say, the song Blurred Lines and Marvin Gaye's Got to Give it Up, which Blurred Lines was found guilty of infringing.
I also found it annoying that the article I linked stated "For a Black creator in an industry that has long appropriated Black culture..." but then goes on to argue that the amount of copying done from Mexican Breakfast is just "the creative process". To be clear, I think it is part of the creative process, but it's annoying the author can see none of the hypocrisy about taking about "cultural appropriation" while then devoting paragraphs to how the copying of Mexican Breakfast is somehow totally different.