But why is @{\@foo} wrong? Whatever the answer is, the same could be said of &foo() (aside from the extremely tiny overhead of taking and dereffing a ref). It's only wrong in the sense that:

 $great_answer=(((1+1)**(1+1+1))-1)*(1+1+1)*(1+1);

is "wrong"; it's too complicated, and "should" read:
 $great_answer=42;

(Alternatively, it's overly complicated for some good reason which was left undocumented, which is IMHO more wrong. :-) )