This track is useful for keyframes that are irregular and do not need interpolation. Each value is held for the entire duration of the keyframe, until the next one comes in. This is the type of animation track that Resonite imports subtitles as, but it can be used for any value. It can be useful also in cases you do your own custom interpolation (e.g. with Smooth Lerp) and just need to change the "master" value.