The implications for our hobby are huge. Put it this way - GTP-3, with the proper prompting, can generate entire adventures. It could produce base classes and prestige classes. Magical items. Villainous and heroic organizations. Cities, towns and villages. NPCs. GTP-4 is just a few years away and will have even greater powers.
The quality of the output is very dependent on what you put into it. GTP-4 will be around 500 times the size of GTP-3, and will also benefit from ancillary advances in neural networks. Because RPGs are rules based and procedure based, its likely that this technology will be able to produce elaborations all by itself.
Every system’s smartness is curtailed by how dumb the builder/programmer/test-data trainer are.
I am highly sceptical of any technology that says it will make things obsolete. Yeah, PC’s would redefine the workplace and workweek, never again would we work as much. Look how that prediction from the 70s came true. We only started working more, in ever evolving ways.
One thing it could do is produce 3.5e statblocks. That could save a tremendous amount of time. How about feeding in a 2E module and have the AI spit it out in 3.5e mechanics? All possible.
I used Play Dungeon IO to produce the following before I hit the paywall. Note that this isn’t direct access to GPT-3. Rather, it uses an API. If you set up your own specifically for D&D you could do great things. What you see here is me giving instructions, and the AI intuiting what I want.