Also, this kind of profiler is great because you can use it on any running Python program, which is pretty magical and very useful. (especially when it's an application you didn't write)

But it's not right for every use case: by design austin/py-spy can only really profile the whole program, and if you want to profile a specific function or endpoint in your program, something like PyInstrument https://github.com/joerick/pyinstrument (which includes Django middlewares & Flask decorators) is a lot more useful.