Items at the top of the Product Backlog need to be small enough to fit into one Sprint. They also need to be clear and detailed enough but not too detailed (eg not with all the tasks identified), as it would be upfront planning. Tasks
are created gradually during the Sprint.Product Backlog items require multiple expertise and usually done by multiple developers. Therefore, they are not assigned. Tasks, however, are assigned to the individual developers, while everyone
stays accountable.