"Jira sucks" is not a useful thing to say.
Yeah, Jira's default workflow isn't awesome. Yeah, it's a giant pain to configure an alternative workflow; and the learning curve to do so is ridiculously steep. Yeah, some BigCorps have configured painfully bureaucratic workflows in it.
But you can also configure it with a very Trello-like workflow.
Why would you use Jira with a Trello-like workflow instead of just using Trello?
Well, for one thing, you get additional features even just on the Kanban board - such as swimlanes.
But the most important reason is that with Jira you get a true database of your issues. One that you can query with a SQL-like language. And one that allows you to present multiple different views of the same data.
For instance, we have a main kanban board for one project. We have a main board for another. We have a kanban board that contains some issues from each specifically for our DevOps person; and another specifically for our QA person. The QA person's board contains three columns that correspond to a single column in the developer's board.
I can create an "epic" that contains multiple tickets (not subtasks or checklist items) that can each progress through the workflow and be deployed independently but still be grouped together under a single parent epic.
And if I want to pull up a list of all Foo component tickets that were filed by Bob before June, implemented by Alice, QAed by Carol, and were released in July - and then open each one in a tab - that's incredibly easy.