One major configuration on a Kanban board are WIP limits (= Constraints in JIRA), which these WIP limits can be added to Columns or Swimlanes.

Examples for Swimlane use where you might want to have a WIP limit: Swimlane per assignee therefore limiting the # of issues assigned to a person; Expedite swimlane where you can only have a small defined number of issues being worked on at a time.

Constraints are available on Columns, but not Swimlanes and should be added.