The design of everyday things should be a must-read for all engineers. I love talking about confusing doors to people I know, they probably all hate it by now!
That's a great example of usability! Developers like us are used to libraries/frameworks and forget most algorithms and architecture (literally the word itself) come from real world examples. We expect the same in usability - get bunch of CSS/UI library and complete the job. This book is useful, if we want to learn about usability from real world examples, rather than cookie cutter CSS/libraries.
I always see people recommend this book, but the reviews on amazon are terrible. I feel like it gets recommended a lot because it's popular/old, not because it's actually good/insightful.
It is insightful and makes us understand the fundamentals of usability - very much like math is for software development. But, it may not be immediately usable for developers in designing web applications. If readers are expecting widgets/screens, they might be disappointed with this book.