My opinion when clicking: definitely yes, they're super helpful to see in a glance what it's supposed to look like and where I'm supposed to click
My opinion after clicking: rarely, because you'd need to capture them in every language/region and recapture them after any significant UI change and make sure it's small enough for users to see who need 400% zoom or are viewing it on a phone screen and you need the text equivalent anyway for blind people
That's not what the author wrote, just my takeaway. The author has recommendations for how to make screenshots work for you, but even with automated screenshot grabbing, it feels like you can count the number of UI updates that can happen until the page doesn't match the textual description anymore (or the URL changes, or the button ID changes so the screenshot grabber can't find the page anymore altogether) on one hand, if not half a hand, so you need to check them all manually after every update anyhow
They're still good for marketing material such as a readme file or project website. I love screenshots because they show features more clearly than the text description and you can see at a glance how easy they'll be to use and whether the offered options match your requirements. That's just a handful of representative screencaps though, not an extensive set that needs to match precisely with a user's steps, so much more maintainable