Actually it's abuse of attributes, since attributes must be metadata only, while data itself should be in element content. But it makes large XML files much more readable ...

Only because you don't tend to find XML tidiers that display like this:

  <node_name
    attr="value"
    attr2="value2">

always this:

  <node_name attr="value" attr2="value2" etc="etc" ad="infinitum" until="you have to scroll">

edit:

On a <person>, how do you define what's data and what's metadata? Is a name data or metadata? What's the difference between data and metadata in the first place, in a concrete, testable definition? Google define:metadata says:

  data about data; "a library catalog is metadata because it describes publications"

So a library catalog should be like this?

  <library name="of congress"
    978_3_16_148410_0="<data title=\"\">contents</data>" 
    978_3_16_148410_1="<data title=\"\">contents</data>"
    etc >

(intentionally reducto-ad-absurdum)