I love reading narrative history, but I also have a background in academic history. As such, I often look for a gray area of works that are pleasant to read, but are still ground in proper citation and stand up to academic critique.
I have never read Guns of August, but I know it’s a “classic.” I see Barbara Tuchman is well regarded and Pulitzer winning, but I am incredibly skeptical of journalists who delve into history.
Are Tuchman’s works worth the read, from an academic perspective?
I've been saying for a few years that Tuchman's Guns of August and Christopher Clark's Sleepwalkers are great bookends for a shelf of material on the origins of WWI. Read Tuchman, and you could be startled to later learn that there was a country called Serbia that was involved somehow. Read Clark, and you could later be amazed to learn the German leadership were greatly involved. I think your doubt about journalists is well founded. They have a tendency to work quickly, prioritize getting it written now over getting it right eventually. That is fine for many of their tasks- say, covering an arson, or a corruption trial. But if the task requires spending a great deal of time with a lot of sources, to understand them well, it can result in an incomplete narrative, or just simply getting something wrong. The Guns is incomplete. To be fair, she picked one of the most hotly-debated topics out there, and one that has so many misleading or difficult sources in numerous languages that it really would have been impossible for her. Even now, it is not likely to be ever really settled to everyone's satisfaction. As long as you can keep in mind that The Guns is a partial narrative, it's fine, the sources it used are valuable. But as far as present academic scholarship on the subject, no, you would not be able to cite it.