One use of Python as a "glue language" I've seen that actually avoids the performance problems of those bindings is GNU Radio. That is because its architecture

One use of Python as a "glue language" I've seen that actually avoids the performance problems of those bindings is GNU Radio. That is because its architecture basically uses python as a config language that sets up the computation flow-graph at startup, and then the rest of runtime is entirely in compiled code (generally C++). Obviously that approach isn't applicable to all problems, but it really shaped my opinion of when/how a slow glue language is acceptable.