We started a project using typing annotations for everything, and it's really a pleasure to use. It's like the type safety of C++ without the insane language complexity; the "advanced" parts of the language usually make intuitive sense.

For our use case of deep learning, REST APIs, and image processing (often a mix of these), Python seems like the best choice we have. The GIL isn't a problem at all because all our computations are done with NumPy or PyTorch, which release the GIL during most of their operations.