Prettier, a JavaScript code formatter, has seen an incredible adoption thanks to its careful handling of the very, very, long tail of ways people can write code. At this point, the formatting logic has been solid and after our work on [ternaries](https://prettier.io/blog/2023/11/13/curious-ternaries...
If I had to guess the motivation, it would probably be that:
Rust is a systems language known for performance and correctness, which makes it a good candidate for their stated goal of having a competitor to encourage performance and correctness within Prettier
Rust is popular and relatively well-known among open source developers, more so than any comparable language except maybe Go
Rust is a hip language that probably added some free publicity to their announcement