It's not about confidence in the code. It's about confidence in having hardware that supports TSX, and will also support TSX next year. As far as I can tell, you still need to ensure that you have correct and reasonably efficient fallback code for platforms that don't or no longer have TSX, unless you're working on a project that can get away with very narrow system requirements.
Put simply, TSX is not mainstream, and isn't on track to be mainstream anytime soon.
Intel's only been shipping server CPUs with non-defective transactional memory for about five years, and a good chunk of those servers have it disabled for security reasons, or did at some point pending better fixes. IBM has dropped transactional memory from their latest POWER processors. Even if we only look at server CPUs, this does not look like a thriving ecosystem.
Put simply, TSX is not mainstream, and isn't on track to be mainstream anytime soon.