This page is specifically talking about A2P (Application to Person) RCS with business messaging rather than Person to Person (P2P). The rich message types shown in the demo are only available for A2P / businesses.

Not a ton of businesses were interested in using RCS until Apple said they would support it. Businesses are now starting to adopt RCS, but for a variety of reasons it'll take a while for it to replace SMS / MMS.

I posted some more info above. Also, it is possible to create a "text us" button, but support (especially on iOS) is flakey. Carriers are not enabling RCS on the numbers businesses use for SMS / MMS in order to help eliminate spam.