Further to JavaFan's point about clarity, there's also no need to go overboard using concatenation for complex hash or array values in a string. They will interpolate just fine:

>perl -wMstrict -le
"my %hash    = ( a => [11,22],  b => [33,44], );
 my $hashref = { c => [55,66],  d => [77,88], };
 ;;
 print qq{$hash{a}[0] $hash{b}[1] $hashref->{d}[1]};
"
11 44 88
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Clarity? 3 extra, not-needed, punctuation characters that hardly anyone ever use?

I fail to see why that brings clarity, or who benefits from it.