Text formats have innate issues when it comes to deserialization: you don't know the size of each field of your data until you scan the entire field. This makes

Text formats have innate issues when it comes to deserialization: you don't know the size of each field of your data until you scan the entire field. This makes deserializers generally more prone to DOS attacks. Many binary formats must necessarily store the size of fields as metadata, which means you might not need to deserialize the whole message to interpret parts of it. Further, JSON doesn't support streaming natively. These are mostly unique use-cases with marginal improvements, but it can matter.