Subpar at what it's supposed to do, extra features don't add a whole lot, mostly made and configured for managers instead of developers. Largely the same reasons people dislike Teams. Has even worse integrations with the Atlassian stack than Teams with the MS stack.

JIRA, just like Teams, is slow, bloated, still won't fix basic issues and largely exists to appease managers. You have to actively work to make JIRA a pleasant experience. It's too easy for most management to make it hell.