>Weird to see people happy to be limited to such stone-age work-flows when fully capable debuggers have existed for almost all proper languages out there the last 30 years.

Even though node has a debugger with breakpoints, etc., an effective programmer will still use logging in situations like the ones in the article. Taking the first example, before he knew that NaNs were causing the problem, setting a breakpoint would have taken forever to reveal anything. You can't set a conditional breakpoint until you know what the condition is. Logging was the fastest way to get useful clues.