Within the space of {schema-ful, schemaless} x {binary, text}, protobuf, {BSON, MessagePack}, JSON each occupy a distinct position. The position (schema-ful, te

Within the space of {schema-ful, schemaless} x {binary, text}, protobuf, {BSON, MessagePack}, JSON each occupy a distinct position. The position (schema-ful, text) is not very meaningful combination in practice and not covered by these, whereas the position (schema-less, binary) is a valid practical use case supported by {BSON, MessagePack}. For example, you don't know the schema before-hand but still want to minimize data size.