Object initializers are the only way to initialize anonymous types, which are types generated by the compiler.
var album = new { Band = "Beatles", Title = "Abbey Road" };
For that reason object initializers are widely used in LINQ select queries, since they provide a convenient way to specify which parts of a queried object you are interested in.
var albumTitles = from a in albums
select new
{
Title = a.Title,
Artist = a.Band
};