if IDE supports converting them into clickable links, then scrolling through a log in its Git integration (kinda like `git log --oneline`) will be a convenient list of links to issues. If the commit messages are good, you just skip over the Jira issue/ticket key/ID. If what you want is to see the requirements of a feature or steps to reproduce of a bug or some other context for the ticket, then a clickable link is very convenient. Of course, sometimes it does make sense to include some of that information in the commit message as well.

When working in big teams, it can be very hard to increase the usefulness of commit messages. On the other hand, enforcing inclusion of a Jira issue key in commit messages is easy to implement. Relying on issue tracker descriptions can be a difficult proposition as well. Quality of individual ticket descriptions can be low; depending on how responsibility for maintenance is handled, the bug tracker migrations can sometimes be handled improperly and information can be more easily lost than in a Git log.

It's probably kinda helpful in git blame.