Lots of repetitive data with a relatively flat structure can be a good argument to get away from JSON, too. Let's set aside binary formats for a moment. I once

Lots of repetitive data with a relatively flat structure can be a good argument to get away from JSON, too. Let's set aside binary formats for a moment. I once sped up populating a large-ish table of data by an order of magnitude - and achieved a pretty decent reduction in data volume, too - just by switching the format to CSV.