Context Map (context_map) in syslog table is the place that provides insight or clues as to the problem script/piece of code causing the message in the system logs.

if you write the code and you know about the logging message if someone else does then it will be challenging for you trace with default view of system logs

So when you include the "Context Map" column in the list, which gives more information about piece of code caused the message. such as

ServiceNow node "_system_id" handled the script

User "_logger_in_user",

sys_id "record_sys_id" of the source script

Table name "table_name" and many more.