If you are running a WordPress site of any kind you can do some things the lazy way. Configuring WordPress SMTP is not one of the things you should be lazy about. Here’s why…
SMTP is the way you send email from your site out. So every user registration, membership email, shopping cart email, etc., that gets sent from your site out to the world uses SMTP. WordPress can do it for you out of the box, so you really don’t need to pay attention to it, unless you run into problems. And it’s likely you could not see the connection so here is a case in point
I found the Postman plugin (one of several SMTP plugins for WordPress) as a fix for two different issues. I had one Gravity forms form that was timing out, another a WooCommerce cart issue that was timing out. I had no idea that both were timing out because they were both failing to send email fast enough (both had to send out 2 emails when the was a form submission – one to the customer, and one the site admin). Once I used Postman to handle my SMTP email instead of the stock WordPress method (PHP) no more hangups occurred.
Funny that WooCommerce support pretty much agreed to disagree that I solved the issue this way!