Well, the (admittedly small) danger is that a call like &bar will pass on the current value of @_ to bar. That's almost never what you want. And even if it _is_ what you want, you'll confuse a maintenance programmer unless you write it as &bar(@_) (or bar(@_)).

#!/usr/bin/perl

sub foo {
  &bar(1, 2, 3);
  &bar; # silently passes on @_
}

sub bar {
  print "@_\n";
}

&foo('a', 'b', 'c');
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Also, in general, less punctuation is good - as the less there is to type, the less there is to get wrong :-)