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)