> Based on the man page it doesn’t appear to be doing anything useful here

The man page tells me:

  -S, --split-string=S
         process and split S into separate arguments; used to pass multi‐
         ple arguments on shebang lines

Without that, the system may try to treat the entirety of "uv run --script" as the program name, and fail to find it. Depending on your env implementation and/or your shell, this may not be needed.

See also: https://unix.stackexchange.com/questions/361794