Some people may prefer using whatever llama.cpp in $PATH, it's okay to support that, though I'd say doing so may lead to more confused noob users spam - they may just have an outdated version lurking in $PATH.
Doing so makes unsloth wheel platform-dependent, if this is too much of a burden, then maybe you can just package llama.cpp binary and have it on PyPI, like how scipy guys maintain a https://pypi.org/project/cmake/ on PyPI (yes, you can `pip install cmake`), and then depends on it (maybe in an optional group, I see you already have a lot due to cuda shit).