Whether using Lua or Python, for GPU-based scientific computing, the need to drop into a C call is the same. The overhead of Python vs Lua never really mattered.
While we were based on top of LuaJIT, we couldn't use the JIT for anything because we had to always call into the C library for GPU kernels (and LuaJIT can't JIT through an opaque C call, incase that C call changes the interpreter stack).
Where Python really helps is with its ecosystem. The entire data science and ML ecosystem is in Python.
The difficulty of calling out to C is not much greater in Python, things like PyBind11 make it pretty natural.
While we were based on top of LuaJIT, we couldn't use the JIT for anything because we had to always call into the C library for GPU kernels (and LuaJIT can't JIT through an opaque C call, incase that C call changes the interpreter stack).
Where Python really helps is with its ecosystem. The entire data science and ML ecosystem is in Python.
The difficulty of calling out to C is not much greater in Python, things like PyBind11 make it pretty natural.