I’ve created a metabox on a CPT that I’ve registered the Piklist way. When I enter text in the metabox and save the post, WP creates a new custom field with the same data. Is this by design?

A features post type, created using a plugin:

<?php
/*
Plugin Name: Features Post Type
Plugin URI: http://www.kj-prince.com
Description: Creates a "Features" post-type the Piklist Way
Version: 0.0.0.1
Author: KJ Prince
Author URI: http://kj-prince.com
Plugin Type: Piklist
License: GPL2
*/

  if (!defined('ABSPATH')) {
      exit;
    }

  // Flush rewrite rules for custom post types
add_action( 'after_switch_theme', 'do_flush_rewrite_rules' );

// Flush your rewrite rules
function do_flush_rewrite_rules() {
  flush_rewrite_rules();
}

  add_filter('piklist_post_types', 'features_type');
  function features_type($post_types)
  {
    $post_types['features'] = array(
      'labels' => piklist('post_type_labels', 'Features')
      ,'title' => __('Enter a new Feature Title')
      
      ,'page_icon' => plugins_url('piklist/parts/img/piklist-page-icon-32.png')
      ,'supports' => array(
        'title'
        ,'revisions'
        ,'editor'
        ,'author'
        ,'thumbnail'
        ,'custom-fields'
        ,'sticky'
        ,'page-attributes'
      )
      ,'public' => true
      ,'admin_body_class' => array (
        'piklist-demonstration'
        ,'piklist-sample'
      )
      ,'has_archive' => true
      ,'rewrite' => array(
        'slug' => 'features'
      )
      ,'capability_type' => 'post'
      ,'edit_columns' => array(
        'title' => __('Features')
        ,'author' => __('Assigned to')
      )
      ,'hide_meta_box' => array(
        'slug'
        ,'author'
      )
      
    );
    
    return $post_types;
  }

A metabox added to the features post types, created by adding the Piklist > Parts > meta-boxes directory scheme:

<?php 
/*
Title: Features Description Metabox
Post Type: features
New: true
*/

piklist('field', array(
    'type'        => 'textarea',
    'field'       => 'features_description',
    'label'       => 'Feature Description',
    'description' => 'Snippet for Feature Description',
    'value'       => 'Awesome Feature',
    'help'        => 'I need help too',
    'attributes'  => array(
        'class' => 'text'
         )
)); 

Now when I enter text into the meta box and save, a new custom field is created with the same name and text, as seen below.

Is this by design?