Basically everything in Linux will create a temp file one way or another even pipes. For you to take a binary and run it directly it has to have an inode. At best you can use Python & the ctypes module to write a program into part of Python's memory and trick it into continuing execution from there.
Pipes are not temp files, they’re more like kernel buffers associated with no file. When I think of temp file, I think of something that is at least associated with a filesystem.
The reason that running a binary needs a file is because execve() takes a path as an argument. But, as you said, there are other ways to load code into memory.
