Developer here - I created PrestoText after finding no suitable solutions during my previous startup. We needed an easy way to send SMS messages to a low number of people. All the other solutions we found were designed (and priced) for sending a larger amount of SMS messages (or text messages).
Other Google Sheet add-ons exist, but they mostly use someone elses phone number to send the messages, so you can't rely on them 1. not reading your messages and 2. someone else using that service getting the number blacklisted. PrestoText allows you to purchase your own Twilio phone number (~$1 month) and send messages from your own Google Sheet. We never see the message content or how many messages you are sending. PrestoText is simply the tool that links Google Sheets and Twilio together.
Other Google Sheet add-ons exist, but they mostly use someone elses phone number to send the messages, so you can't rely on them 1. not reading your messages and 2. someone else using that service getting the number blacklisted. PrestoText allows you to purchase your own Twilio phone number (~$1 month) and send messages from your own Google Sheet. We never see the message content or how many messages you are sending. PrestoText is simply the tool that links Google Sheets and Twilio together.