I am glad that we decided to pick CSV as our default format for health data (even for heavy stuff like raw ECG). Yeah, files were bigger, but clients loved that they could just download them, open in Excel, make a quick chart. Meanwhile other software was insisting on EDF (lighter, sure) but not everything could handle it.

And at this point, "lighter" is immaterial.

"Hi, I'm sending you a two-line statement in a Word document. It's 10kB."

"Thanks, I took a screenshot of it and forwarded it. It's now 10MB."

"Great! That's handy!"