Android Oreo in itself is a fine operating system, polished and ready for you to use. However, not all markets can afford devices that are expensive. In a lot of emerging markets such as India, Indonesia, and the Philippines, a cell phone is their first point of access to the internet in their lives, ever. The budget that they have is also limited, with a lot of people buying devices priced under $80.
Android Oreo Go Edition marks Google’s attempt to build Android centered around the “next billion users,” who will use a cellular device as their first point of access towards the internet. Naturally, a lot of Google apps that are built center themselves around the US cellular market. However, with Android Go, Google has worked with teams stationed in India to tailor an experience best suited for new users with low powered devices.
Tl;Dr: “Go” is the lite version of everything. YouTube Go, Google Go, Android Go.