Anything that suggests curl into bash just plain sketches me out. (edit: I know, this isn't totally rational, it just seems weird to me. We download and trust a lot of software and run code from a bunch of package repositories as a regular activity...).
Git clone llama.cpp and build it, it's not hard.
https://github.com/ggml-org/llama.cpp/blob/master/docs/build...
literally just a few steps for the basics:
git clone https://github.com/ggml-org/llama.cpp
cmake -B build
cmake --build build --config Release