I use it all the time. I know (some) people think it is bad practice, but in my mind it fits. It nicely groups thing that are equal. $cow is the current cow to work with @cow is the heard of available cows and %cow is nicely collecting the properties of each cow, so $cow{$cow}{weight} makes perfect sense to me. YMMV.

I sometimes doubt to use @cows (which works well in foreach my $cow (@cows) {) or @cow (which works better with milk ($cow[$_]) for 2, 5, 7..9;).