Spacing decides everything
Exporting every frame of a 30 fps video yields 1,800 images per minute, which is a large ZIP and a slow export. Most uses do not need that. A dataset usually wants variety rather than near-duplicates, so one frame per second — or per half second — gives more useful coverage than consecutive frames that are nearly identical. Rotoscoping and frame-by-frame animation are the exceptions that genuinely need every frame. Set the range first, then choose spacing based on how many images you actually want.