Exciting changes for python

I wrote "experiment". Obviously, interpreted languages catch much fewer bugs at compile time and require a lot more test coverage. You absolutely need a ton of test coverage when refactoring and it tends to be never enough. Introducing regressions in less usual cases is bad indeed, but that does not get in the way when experimenting new designs to address performance bottlenecks in _common_ use cases. It only comes back and bites you later but that's not specific to performance, that's just the nature of all interpreted languages and that's the price to pay for a much faster development and prototyping loop.

When I wrote "safer" I had memory corruption and C/C++ specifically in mind - these are always the most-time consuming bugs by several orders of magnitude. There are indeed many other options besides Python and C/C++ and some may be better than either depending on the use case.

Compared to lower level languages, Python saves time prototyping not just because you write less code but also because there are very high level libraries and approaches to choose from, especially for I/O and concurrency.