A binary format you understand is easier to parse than a text format, but a binary format you don't understand is harder to learn (from reverse-engineering file

A binary format you understand is easier to parse than a text format, but a binary format you don't understand is harder to learn (from reverse-engineering files) than a text format following certain conventions (HTML/JSON is more familiar to readers than PDF or Punycode). And text formats are easier to extract information out of fragmentary or corrupted documents than binary (or worse yet compressed) formats.