This works cleanly for a freelancer running their own hours through FreshBooks. It breaks down the moment a team already tracks time somewhere else, a project tool like Asana or Trello, a dedicated time tracker, or a field-service app, because none of that logged time shows up in FreshBooks on its own. Someone ends up re-entering a week's worth of hours by hand just to get them billed, which defeats the point of tracking them accurately in the first place.
Mileage has a quieter version of the same gap. It's logged correctly on the phone, but matching it to the right reimbursement category or tax treatment outside FreshBooks is still a manual lookup for whoever closes the books.