Is advised to use CRDTs for an offline app that syncs to a central server, such as a todo app like Apple's Reminders or Todoist? Can simpler methods suffice ?
You can if you like but, with a centralised server, you can do all the merging logic in one place without a CRDT. With a CRDT, you'd be storing the entire history of a document, which might be overkill for something like a todo app that's just doing last write wins.