Well, hopefully we can at least get some cool games out of it. Canned NPC dialog is one of the biggest immersion breakers in open-world games / RPGs.
On the topic of societal impact of GPT-3 (and subsequent models) - structurally, how will people's use of the Internet change once it becomes common knowledge that nearly anything could have been written by a bot? On the one hand, I find the notion of competing trollbots screaming at each other into infinity to be rather amusing, but on the other hand I'm not keen to return to a world where I can only be sure I'm communicating with a person if I know them in real life.