JIRA contains more context than you can put in even most elaborate comment. For example links to duplicates, test cases, screenshots, core dumps, discussion wit

JIRA contains more context than you can put in even most elaborate comment. For example links to duplicates, test cases, screenshots, core dumps, discussion with testers/customers, etc. And it's updated over time. Would you change the commit message if a tester noticed something about your explanation of the bug was wrong but the fix still works? Additionally the context is already there in the JIRA, retyping it in detail in a different format into the commit message is more friction for little benefit.