Damien Conway weighs in against this in his "Perl Best Practices" book. In the section titled "Cloning", p. 334 he argues that blending object creation and cloning makes it harder to tell what the code is doing, e.g.

my $obj = $name->new( @args );
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Might be doing creation or cloning depending on whether $name is a string or a reference. Also he makes the point that it complicates the constructor code for no good reason.

So yeah, this is a slick trick that people used to like, but it's gone out of favor.

(You can blame Conway for helping to promulgate this idiom: he uses it in places in his earlier work "Object Oriented Perl".)