You're the first person I've ever seen call matplotlib "user friendly".
high energy physics
lots of computational bio
fluid dynamics
rendering
In general, python and matlab really struggle in problems where you want maximum performance, but the most efficient algorithms aren't vectorized. In some cases, this is solvable by writing python libraries in C/C++, but especially in scientific fields, the end users are often the same people writing the algorithms, so they don't gain much from a python library if they have to do all the hard work in C++ anyway. Julia gives them a way more productive dev experience while still having a good user experience.
indeed, the grants (in the millions $) given to rewrite C++ or Python just to handle array (because for loop sucks) and ends up making monorepo blobs is jaw dropping -- while it's almost free in Julia, with 1/100 of the line of code and more flexibility we can match and beat even C++ code...