It's like markdown, but for data.

Just like markdown provides a quick way in that to renderize something pretty, but is still readable in plain text, recfiles do the same for data, it has data types, keys, integrity, and is easily queryable with its tools, and also easily read in plain text.

Sure, you could use some type CSV, but that is not pretty to read as recfiles. The point is the same as markdown, usable as just text, but with good tooling around it.

with markdown files in a dirs, you would have to provide you own tooling.