Julia's main selling point over Python is its speed, but most Python deep learning libraries are just wrappers around C/C++/Fortran/CUDA/Cython codebases that are as fast or faster than Julia.
“Metaclasses are deeper magic than 99% of users should ever worry about. If you wonder whether you need them, you don’t (the people who actually need them know with certainty that they need them, and don’t need an explanation about why).”