RCS also has all the same problems as SMS and Google Allo when it comes to how you should architect a messaging service. RCS will use your carrier-owned phone number as your identity online, instead of an Internet-based account system. Changing Internet identity from a free email account to a paid number owned by a carrier is a terrible and, I would argue, immoral idea. Tying online identity to the ability to continuously pay a phone bill is straight-up discriminatory toward people of lower income. There should not be a risk of losing your online identity if you stop paying your bill for a month or change phone carriers. There's no upside to phone number identity at all, yet Google keeps doing it.