It's only 25% speedup in actual Python code, in domains like data science this won't matter much, because your cpu cycles are mostly spent inside numpy.

It does matter if you run your ML models in production. After we upgraded to 3.12 the average response time ~4-6ms decreased to stable sub 2ms. Latency decrease for p95 and p99 were even more significant

There are plenty of web apps running in pure Python. It matters a great deal for them.