The primary problem, which seems common to LLMs asked to do this stuff, is "very high level output" - a content smoothie, with few features that are particularly specific to the prompt. The marketing campaign in the OP is so generic, you can `s/Saturn Parable/Any other educational product` and it's still "fine". Similarly the emails - there are 1 to 2 sentences that are product specific, and a bunch of fluff. If I paid a marketing agency for this, I'd be very disappointed.
The LLM isn't demonstrating much more than "Generic templating ability over a large range of templates" in this instance. Whilst that's probably 50% of the jobs in the world, such jobs were already at risk of someone searching for "Basic X template" and expanding the placeholders themselves. I think I could do a similar job in 30 minutes by doing exactly that.
LLM's main wins seem to be providing a single unified entry point to all the templates in the universe. It's a "Universal UI", rather than a "Content creator". I guess I shouldn't discount the value of such a thing, once we get the "Sometimes it just lies" problem under control.
The most interesting immediate thing here is the image generation - that's pretty good, and a big saving over scraping through stock images. I suspect the demise of stock image providers to be the first palpable win for generative AIs, if the copyright question doesn't bog this whole field down.