Difference between Logger integration and System_log Integration?

[wanton trail]

I'm building an elaborate automation to turn devices off or on, triggered by persons entering the home. The automation currently involves a Choose block, multiple AND and IF blocks, and IF/ELSE blocks will probably be added. Since it is an elaborate yet vital automation, I want logging in many places so debugging becomes easier. But I don't know now whether I should use the Logger integration or the System_log Integration to write custom logrules to the Logbook. Can anybody tell me the difference(s) between the two and which to use in which use-cases? Which integration should I use for my described use-case?

[sleek flax]

Logbook is yet another separate thing: https://www.home-assistant.io/integrations/logbook/#custom-entries

logger configures the logging service through level and filters

system_log writes to the log and generates events when things are written to the log

logbook, now called Activities is an event log separate from the others that you can write to or receive events from

You should use system_log because it's easier to read and filter, IMHO

I also hope you're aware that traces exist for all runs, so consider whether you need additional logging

[wanton trail]

Yes. I use this one for low complexity logging but not for debugging purposes. Just the simple things that other residents could also understand. That is the correct use of this, right?

[wanton trail]

I think this is what I am searching for. To write stuff to the log like WARNING: automation ABC cannot execute Action DEF because entity GHI is unavailable.