Yes, this behaviour is intended, according to §184.108.40.206 Initialization by list-initialization
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
Tand 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
Tand the argument list consists of the
elements of the initializer list.
As to “the whole purpose of uniform intialization”… “Uniform initialization” is a marketing term, and not a very good description. The standard has all the usual forms of initialization plus list-initialization, but no “uniform initialization”. List initialization is not meant to be the ultimate form of initialization, it’s just another tool in the utility belt.