That is not correct - bless alters its first argument in-place:

use Data::Dumper;

my ( $ref1, $ref2 ) = ( {}, {} );

my $ref3 = bless $ref1, 'Foo';  # capturing results
bless $ref2, 'Foo';             # in void context

print Dumper $ref3;
print Dumper $ref2;
__END__

# results identical:
$VAR1 = bless( {}, 'Foo' );
$VAR1 = bless( {}, 'Foo' );
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bless returns the reference as a convenience, however it certainly operates on the reference. (It doesn't alter that which is referenced {the "referent"?}... but he's not doing that, and that isn't what you are demonstrating either.)