As The Verge noted, Google’s advantage may simply be the sheer variety of Google Fi devices that support RCS. This will include Pixel phones, LG’s G7 and V35, and Motorola phones like the G6 and Android One-based Moto X. Rival carriers have typically limited you to one manufacturer, such as T-Mobile’s Samsung support and Engadget parent Verizon’s compatibility with the Pixel 3. You’re still out of luck with iPhones and most off-the-shelf Android phones, but it’s a start.
There’s another improvement coming for a wider range of devices. Google Fi will support faster LTE data in 33 countries over “the next few weeks,” including most of Europe (UK included), Scandinavian countries, Hong Kong, Iceland and Israel. You’ll still need a designed-for-Fi phone to take advantage of the new speeds, but it’ll be helpful if you’re determined to Instagram your entire vacation.