We once walked into a client meeting with a large international company who had just been audited by a government agency. The auditor had quite sensibly asked to see some evidence of completing the 425 safety critical actions which had been generated on one of their facilities.
You can probably tell where this is going - they couldn't produce any evidence that they had completed any of the tasks in the actions, and as a result had to suspend production.
Of course not every action is safety critical, but if it's important enough to record then I would propose that we need some way of confirming that the work has been done, and also to be able to simply 'take a look' at the status of an action.
Complex or important actions may need to be signed off by multiple people with a mechanism for rejecting or approving the work done (with suitable comment to inform any required corrective action), and this is where sticky notes and spreadsheets really struggle. Even pretty straightforward actions can generate a fair bit of data, and it's often handy to have somewhere to attach documents or images if these form part of the action or proof of action completion.
Tip #4 – Specify a due date - otherwise why bother