SMS is one of the different way to reach customers directly without caring about opening message rates or spam tools.
We have noticed on some stores when customers bought some products, they didn't
care about the email send and the newsletters, that's making they can miss a big deal or a promotion.
To avoid it, what about using SMS on our stores, in add of sending emails it's a good idea? ( don't you think? ), to send SMS to let him know about the way is order is going, to let him know about next promotions he shouldn't miss or sometimes share some coupons code he can use.
If you want to do all of this with SMS, the plugin Ultimate SMS Notifications for WooCommerce is the one you need on your store.