Why is the std::initializer_list constructor preferred when using a braced initializer list?

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§13.3.1.7 [over.match.list]/p1:

When objects of non-aggregate class type T are list-initialized
(8.5.4), overload resolution selects the constructor in two phases:

  • Initially, the candidate functions are the initializer-list constructors (8.5.4) of the class T and the argument list consists of
    the initializer list as a single argument.
  • If no viable initializer-list constructor is found, overload resolution is performed again, where the candidate functions are all
    the constructors of the class T and the argument list consists of
    the elements of the initializer list.

If the initializer list has no elements and T has a default
constructor, the first phase is omitted. In copy-list-initialization,
if an explicit constructor is chosen, the initialization is
ill-formed.

As long as there is a viable initializer-list constructor, it will trump all non-initializer-list constructors when list-initialization is used and the initializer list has at least one element.

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