Performance is basically the same (in microbenchmarks), they went as far as preserving the use of red black trees for an apples to apples comparison, but it’s going to improve security as binder runs inside every process.
That means binder is going to join Asahi graphics, the Android Bluetooth stack, and puzzlefs in the serious drivers written in Rust club.
This could be interesting, a bit worried how this will effect existing binder in distros and DKMS modules since waydroid relies on these
The C binder driver has been in the mainline kernel for one or two years at this point.