[sparky]

Python's standard library includes a lot of functionality that only really makes sense on top of an operating system, e.g., filesystem operations, inter-process communication. By the time you implement that kind of thing, plus drivers to communicate with the peripherals on your embedded platform, plus a TCP/IP stack, you have an operating system. Maybe you have a small RTOS instead of Linux per se, but that's a different question than 'bare metal' (and I dare say more embedded systems are running with at least an RTOS than without).

[Aegean]

You don't really have to have networking or files to write programs. Currently in a baremetal embedded system (I am including the RTOSes) you can write programs in C or C++. It would be very useful to be able to write programs with a main() function using python. You could write an interactive shell, device drivers, even a small operating system. So what I mean here is instead of aiming for applications, you could use python to write system software.

I think there are already lua interpreters ported in this way but python is more common and perhaps easier to use.