In my opinion it's a range of management requests that give rise to the workflow, and devs hate managing workflows with email, notes ("When you are done implementing move the issue to the X column and send a message to the testers group that..."). So then devs bring in JIRA to do some automation. Now the tester person gets an email when the issue is moved to the testing phase. But once everything is in place, management will see the benefits, and the workflow will "evolve", especially if the teams grow. It's pretty natural.

I used to be a dev who brought in JIRA because I like it out-of-the-box and it can grow with a team. But I always tell my manager to NOT TOUCH THE WORKFLOWS and to just let things grow organically as the needs of the team grow (or don't). And every time the moment they click around and see the workflow editor we ended up with some big, bloated, convoluted mess. I've been burned too many times, I no longer recommend JIRA to anyone.