For the first time in history, there is an edition of D&D that actually lets you roleplay.
Never before has a set of game rules enabled people to tell cooperative stories in a fantasy setting. In Dungeons and Dragons Fifth Edition, finally you can use your imagination. You can adjust, add, or ignore rules as you see fit, which was impossible in every other edition of D&D. You can use a grid, which 5E is designed for, or you can play without one and just kind of guesstimate everything. Can you do that with any other edition of D&D? Technically yes, but literally no you cannot.
Where will you go when you start up your campaign and stream it on Twitch? The Forgotten Realms? Some other part of the Forgotten Realms? That specific D&D setting is open to you like it has never, ever been before!