You’re still using Google’s servers even if you’re on iPhone, though now Google shouldn’t be able to read your messages.
It’s just that Apple didn’t want to support Google’s proprietary encryption protocol. So they worked to make end to end encryption part of the RCS standard, and now that it is, Apple is willing to support it.
Edit: Small correction. It seem’s like RCS on iPhone does not always use Google servers. It’s just that US carriers have partnered with Google to provide their RCS support.
You’re still using Google’s servers even if you’re on iPhone, though now Google shouldn’t be able to read your messages.
It’s just that Apple didn’t want to support Google’s proprietary encryption protocol. So they worked to make end to end encryption part of the RCS standard, and now that it is, Apple is willing to support it.
Edit: Small correction. It seem’s like RCS on iPhone does not always use Google servers. It’s just that US carriers have partnered with Google to provide their RCS support.