Its curse, is its developed by Atlassian. A company that was capable of buying Stash, and, somehow, somewhat, turned that codebase into what we now know as bitbucket.
When BitBucket was acquired they were cloud only, and when Stash launched it was on-prem only. We used Stash and BitBucket Cloud around that time at the place I was working and I can definitely tell you that on-prem Stash was definitely not a reskinned on-prem BitBucket Cloud; for one I’m pretty sure BitBucket Cloud was written in Python (Django) and Stash was a typical Atlassian Java product.
The best part of Jira is because it is so flexible, no matter how your process slightly deviates from a basic trello-like board, you should be able to make one or two adjustments in JIRA and have it reflect that.
That's not true of literally any other workflow piece of software I've used, and I've used a ton.
That said, because all the other types of workflow management software I've used are significantly more opinionated and limited, they also limit how bad of a process a bad project administrator can create in them as well.