Some were more creative in nature, and some were more analytical. For example, ideas on marketing sneakers versus an analysis of store performance across a retailer's portfolio.
In general they found that GPT4 was helpful for creative tasks, but didn't help much (and in fact reduced quality) for analytical questions.
I think these kinds of studies are of limited use. I don't believe raw GPT4 is that helpful in the enterprise. Whether it is useful or not comes down to whether engineers can harness it within a pipeline of content and tools.
For example, when engineers create a system to summarize issues a customer has had from the CRM, that can help a customer service person be more informed. Structured semantic search on a knowledge base can help them also find the right solution to common customer problems.
McKinsey made a retrieval augmented generation system that searched all their research reports and created summaries of content they could use, so a consultant could quickly find prior work that would be relevant on a client project. If they built that correctly, I imagine that is pretty useful.
GPT4 alone will especially not be that useful for analytical work. However, developers can make it a semi-capable analyst for some use cases by connecting it to data lakes, describing schemas, and giving it tools to do analysis. Usually this is not a generalist solution, and needs to be built for each company's application.
Many of the studies so far only look at vanilla GPT4 via ChatGPT, and it seems unlikely that, if LLMs do transform the workplace, that a standalone ChatGPT is what it will look like.