only one idiom

But that is the absolute antithesis of what Perl (and all VHL languages) are all about.

We could (and for a while did) program using just a single flow control idiom: goto. If reducing the number of idioms we used was a virtue, we'd still perform the initialisation like this:

my @e = 'a'..'z';
my @n = 1..10;

my $href;

my $ie = 0;
OUTER:
my $e = $e[ $ie ];
my $in = 0;
INNER:
my $n = $n[ $in ];
$href->{ $e }{ $n } = 1;
$in = $in + 1;
if( $in < @n ) { goto INNER; }
$ie = $ie + 1;
if( $ie < @e ) { goto OUTER; }
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We don't any more for very good reasons.

You've pointed out many times that the C-style for loop is far more flexible than the perlish for loop, but we have both and most people prefer the latter for most uses. (Albeit that some use it when it is less appropriate.)

Using one idiom instead of more improves readability, IMO

IMO, if you think about it a little more, you'll change your mind.

By definition, the more general an idiom, the more situations it is applicable in. Which, also by definition, means the more closely you need to inspect it to understand which of those situations it is being used for in this case.