I still find them helpful when the change is outside the cope of the current task. I especially like the ones that include both a reference to a Jira ticket (or similar), and an explanation of why, or any gotchas:

    # TODO: (CAFE-1256) Refactor steamed-liquid stuff to support non-dairy options
    #     We don't currently support non-dairy coffee additives, but once we do 
    #     we will need to ensure that the steamed-liquid transport 
    #     also alerts when users have a dairy allergy.

This is a lot of stuff to add for some things, so we might not want it everywhere, but it helps explain to a reader why we don't currently have it built (product doesn't need X yet), but also has hooks to existing (planned/canceled) tickets and is easily greppable (e.g. "non-dairy" or ticket name).