Hi @nomadicblues ?? The short answer is yes, as soon as Postman is configured, all WordPress emails are sent via Postman (either SMTP or API). Postman will even redirect email from WP Mail SMTP.
But you have a misunderstanding of the basics, so here is the long answer.
When you use WP Mail SMTP, it re-configures the included wp_mail function to use either PHP mail or SMTP.
What is PHP mail? It is a wrapper for sendmail (an operating system command for sending mail) pre-configured with the SMTP options: localhost on port 25 with no authentication and no security. This is incredibly useless and creates an enormous amount of mail failures in modern systems. That’s why it’s not included as an option in Postman.
All email is SMTP and when you choose the SMTP method in WP Mail SMTP, this simply means you are now in charge of setting the host, port, authentication and security options. Then WP Mail SMTP pushes your settings to PHPMailer, an SMTP library included with WordPress, and off your mail goes.
Postman does not work like that. It completely rewrites the WordPress wp_mail function and replaces the default PHPMailer library with the more powerful Zend_Mail library (this is what allows the OAuth 2.0 configuration). Any software on your site that makes a call to wp_mail ends up delegating email delivery to Postman. Including WP Mail SMTP.
From your description, it seems that FormCraft either sends email itself via PHP or via SMTP, instead of using the WordPress wp_mail function. This means that it might not be compatible with any WordPress mail plugins, Postman or WP Mail SMTP. Unfortunately since it is paid-only, I can not look at the source code to confirm.
