Nothing will connect with your customer at the right time better than SMS.
Current figures are that over 98% of SMS messages are opened, and almost all within the first 3 minutes. Nothing else comes even close to these figures as far as efficiency or speed. What it means is that you can interact with your customer quickly and effectively.
What makes it particularly effective is that the message is delivered directly to your customer. Emails are often now protected by ISP spam and customer's filters. These often block your messages.
There is, of course, the higher cost, but you often get for what you pay.
If you have products that need an instant response, you may need it.
PS Another good idea in some industries is to send a thank you SMS automatically every time they buy.