• freeCodeCamp.org / What Are Logs in Programming? If you've ever had a program crash silently with no error message, then you know how important good logging is. Logs help you keep track of what your program is doing so that, if something goes wrong, you know where to look first.
• Honeycomb.io / Logging Best Practices: An Engineer’s Checklist
  • Хабр / 10 лучших приёмов логирования для разработчиков

Versus

• Tracing is often compared to logging. However, tracers and loggers are two different tools, serving two different purposes. Tracers are designed to record much lower-level events that occur much more frequently than log messages, often in the range of thousands per second, with very little execution overhead. Logging is more appropriate for a very high-level analysis of less frequent events: user accesses, exceptional conditions (errors and warnings, for example), database transactions, instant messaging communications, and such. Simply put, logging is one of the many use cases that can be satisfied with tracing.