> "If I was a creative writer then I think the AI could help me with plot outlines or get over writing blocks. But otherwise I'm not grasping why this is going to automate some huge number of jobs."

Writing definitely looks like the key use case. The New Yorker used GPT-3 to write the concluding sentence for one of their articles [0], and I believe The Economist did the same (but for a slightly greater length; though I couldn't find the source just now). It's actually a bit hard to come up with a good conclusion, so this could save some effort and trouble. Separately, GPT-3 can also likely be used for articles about sports, especially if the purpose is to track changes on a scoreboard and present the changes with an article written in prose, versus displayed in a table.

It's quite fair that marketing blogs may not be interesting to many readers, but they can be useful for SEO/boosting the search engine rankings of a website. So, a cash-strapped early or small company could save money from freelance copywriting to GPT-3 if they're not looking for anything fancy, and a lot of people work as freelance copywriters.

I agree that this may not displace anyone in the high-end/high quality segment of copywriting, but it could reduce demand for content farms in the future (i.e. any application where low-quality copywriting written on a short notice is in-demand).

[0] https://www.newyorker.com/magazine/2019/10/14/can-a-machine-...