Because launcher is a shell script and not a Rails application, production.log under the rails directory in the log file logs only Rails info, not shell script info from launcher. It logs all Rails actions, mostly all after the Rails app (Discourse) is running.
The './launcher logs` routine is an alias for $docker_path logs $config
which is the docker log.
Hence, to get all the information from all launcher processes from the launcher script, it will be necessary to tee
(or use another method) the output to save the output to a file if you want to view the information in the terminal and not redirect the output to a file (redirect STDOUT). If you redirect the output to the file, you will not be able to see the output in the terminal.
This is why the tee
command was created, for this purpose 
So, if you want to capture the full output of the launcher script, I recommend you use tee
. It works well for this type of thing.