This script will award myCRED Points when a "Post" is published in WordPress. To define which tags gives points, the amount must be saved in the tags description field.

Award Points based on Tags

/**
 * Award myCRED Points based on Tags
 * This script will award points when a post is published based on
 * what tags a post has. The amount is defined in the post tag description field.
 * Requires myCRED 1.4 or higher!
 * @version 1.1
 */
add_action( 'transition_post_status', 'mycred_pro_points_by_post_tags', 10, 3 );
function mycred_pro_points_by_post_tags( $new_status, $old_status, $post ) {
	// Make sure myCRED is installed
	if ( ! function_exists( 'mycred' ) ) return;

	// Only award points when a "Post" gets published
	if ( $new_status == 'publish' && $old_status != 'publish' && $post->post_type == 'post' ) {

		// Load myCRED
		$mycred = mycred();

		// If the post author is excluded from using myCRED, leave now
		if ( $mycred->exclude_user( $post->post_author ) ) return;

		// Get all the tags that are connected to this post
		$tags = wp_get_object_terms( $post->ID, 'post_tag' );

		// If there are tags
		$total = 0;
		$tags_used = array();
		if ( ! empty( $tags ) && ! is_wp_error( $tags ) ) {

			// loop though tags
			foreach ( $tags as $tag ) {

				// Value should be stored in description
				if ( empty( $tag->description ) ) continue;

				// A value is set, add this up
				$total = $total + $tag->description;

				// Save the id of this tag for the log
				$tags_used[] = $tag->term_id;

			}

		}

		// No need to continue if no tags with points were found
		if ( $total == 0 ) return;

		// Make sure value is formated for myCRED
		$total = $mycred->number( $total );

		// Make sure points are only awarded once
		if ( $mycred->has_entry( 'publishing_content', $post->ID, $post->post_author ) ) return;

		// Award points
		$mycred->add_creds(
			'publishing_content',
			$post->post_author,
			$total,
			'Points for published post',
			$post->ID,
			array(
				'ref_type' => 'post',
				'tags'     => implode( ',', $tags_used )
			)
		);

	}
}

Great script! It's exactly what I was looking for! I'm using it for a custom post type.

Because I need the tag description for my tag archive page, it would be great if I could tweak the script in a way that the value does not come from the tag description, but instead from an ACF custom field (award_points) that Is attached to the tag.

Ideally, I would use something like this:

// Value should be stored in custom field
if ( empty( $tag->award_points ) ) continue;

// A value is set, add this up
$total = $total + $tag->award_points;

Maybe it's a stupid question. I'm not a developer... ;-)