Expo and react-native-fast-image

Mosh encouraged people to upvote the feature request for react-native-fast-image, and so when I visited the page I saw that it had been marked as complete:

https://expo.canny.io/feature-requests/p/react-native-fast-image

expo install react-native-fast-image expo-dev-client
Build locally with expo run:ios and expo run:android
To be clear, react-native-fast-image will not have been added to the Expo Go app that you download from the App Store or Google Play Store.

In other words, we are leaving expo go, and getting into development builds

My question is, what are the implications of going down this route? Or more specifically, what are the limitations of trying to solely stick to Expo Go? What is it that stops expo using react-native-fast-image when we have already npm or yarn installed other libraries?