I think facebook events is more catered towards events i.e weddings, parties etc and not the weekly casual hangouts we do with our friends. Moreover I haven't met a lot of users who actually use it despite it being around for a long time.
About your question, the user doesn't have to enter any information for ETA. The app calculates that based on the hangout destination and your current location.
About your question, the user doesn't have to enter any information for ETA. The app calculates that based on the hangout destination and your current location.