Errand's listing describes turning administrative requests into steps, drafting, finding contact routes and tracking replies. It says messages or spending under your name require approval and identifies tasks it cannot perform.
Apple documents Reminders lists, scheduled reminders and shared lists for organizing tasks on its devices.
A reminder is enough when you already know the next step. Errand's listing is aimed at helping prepare the administrative work itself, while Apple Reminders organizes tasks and alerts. In either workflow, preserve evidence of actual sending, acknowledgement and resolution. The timeline companion helps with that record but does not communicate with the business or update either app.
Comparison based on current official descriptions, not hands-on testing of the competing product. Prices, subscription eligibility and feature availability can change.