Just found out that you can send SMS texts for free

Yes, it is possible to do this. It is also possible that the email gateway address will change over time.

It is not only possible but likely you will be cutoff if you try to send "too many" texts this way. "Too many" is vaguely defined by the carriers as more than "personal use".

> you can send SMS texts programmatically just by sending an email to your mobile carrier

Each carrier has their own email-to-SMS gateway (e.g., Verizon has vtext.com), and you'd need to send an email to the recipient's mobile carrier (not to your mobile carrier).

This has been used for a long time. My business partner had a web form on our website that would send his mobile phone a text message for people to reach him without giving out his mobile number. This was used before the iPhone and other smart phones.