Not a fair comparison since the JSON case includes the outer list as well. And whenever I've seen the equivalent of this in a real-world XML format it would use a <phoneNos> tag to group the phone numbers together.
• Many XHTML and SVG elements can occur without dedicated wrapper elements.
• In Atom feeds, <author>, <category>, <contributor>, <link> elements can occur multiple times without a dedicated wrapper element.
• In XSPF playlists, <link>, <meta>, <extension>, <location>, <identifier> elements can occur multiple times without a dedicated wrapper element.