How do automated tests affect development team productivity?

How do automated tests affect development team productivity? Feedback? Quality? Speed?

1. If we have automated tests: When a developer works on some feature or bug fix, we can have confidence that the change or bug fix won’t break what’s already working.

Benefit: Really short feedback loop, the developer themselves can know whether they broke something, and can fix it immediately.

2. BUT if we don’t have automated tests: the developer can make a breaking change and they won’t know it… until it reaches QA.

Problem: Long feedback loop, the developer must wait for QA to detect that something is broken. Late fixes are more expensive, and requires time-consuming re-testing.