@evan @tom People use OTT services instead of SMS/MMS because:

- MMS isn't great at groupchats.
- SMS/MMS' attached voice calling feature is also not great at groupchats, and doesn't have video chats.
- Common MMS apps lack many quality-of-life features for larger group chats.
- Phone numbers are an insecure, hard-to-change, globally-unique identifier with major privacy problems. Alternatives address those issues in various ways.