Once RCS support rolls out on the iPhone, any cross-platform chat will have all the same advantages and features as iMessage, including read receipts, typing indicators, and high-res image sharing. Why bother jumping through loopholes when you can get the same experience using the native chat app?
We will see if RCS brings the same features of iMessage (it’s not going to be 1:1) and without E2EE I’ll continue to talk to my Android friends on another platform anyway.