Bad logic in set_content_type ?

Should’t set_content_type be like this:

function set_content_type( $content_type ) {
			// Only convert if the message is text/plain and the template is ok
			if ( $content_type == 'text/plain' && $this->check_template() === true ) {
				$this->send_as_html = true;
				return $content_type = 'text/html';
			} else if ( $content_type == 'text/html' ) {
				$this->send_as_html = true;
			} else {
				$this->send_as_html = false;
			}
			return $content_type;
		}

Note I set send_as_html to true if content_type is text/html

https://wordpress.org/plugins/wp-better-emails/