Here's one reason not to use Params::Validate.

The code (minus the inline stuff), in Re: Inline Subs Revisited takes just over 4 1/2 minutes to run.

Modify those subs to validate their parameters using P:V like so:

sub max {
    validate_pos( @_, { TYPE => ARRAYREF } );
    my ($list) = @_;
    my $max;
    for (@$list) {
        $max = $_ if ! defined $max || $_ > $max;
    }
    return $max;
}
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And it takes almost 22 minutes.

And achieves nothing that couldn't be done with die unless ref( $list ) eq 'ARRAY';. (That costs nothing measurable.)

Its like trying get better fuel economy by adding a large, copper-wound electric motor and 50Kg of batteries to your car.