I don't now what that example is trying to show, but let's expand:

perl -l
*r = ["goose"];
*r = \"moose";
print ref \*r;
print ${*r};
print @{*r};
__END__
GLOB
moose
goose
[download]

So you see, GLOB is a useful value in this case. In anycase - if ref() returns a true value, THAT means there is something to dereference here.

Just to make it clear: ref($r) returns "REF" if $r is a reference to a reference.

On the other hand, I agree that the REF return value just adds unnesessary complexity and returning SCALAR for a ref-to-a-ref would have been more consistent and simpler (just like an arrayref returns ARRAY, and doesn't care about the elements of the array).