I own this book and I'll tell you it's not easy learning math from this book. Most of it is just very light overview. There are much better rigorous textbooks that are simpler and more complete.
There are some great textbooks translated from Russian. Analysis by Kolmogorov, (rigorous) Linear Algebra by Shilov, Complex Analysis by Markushevich to name a few.
The book covers too much to be thorough. Each chapter gives good introduction to the subject matter and ends with list of suggested reading.
I always read the relevant parts from this book before going deeper. Not everyone is going to dwell into non-euclidean geometry, functional analysis and topology.
Furthermore, I don't think typical self studying engineer in Hacker News wants to learn math using rigorous introduction to analysis. You can get good working knowledge and intuition without knowing what delta epsilon is.
I agree with you, that book is great for giving an overview of the general areas of mathematics and for providing context before going deeper into an area. I've used it to get some background in the courses I'm taking classes on before the semester starts and have found that really helpful.
There are some great textbooks translated from Russian. Analysis by Kolmogorov, (rigorous) Linear Algebra by Shilov, Complex Analysis by Markushevich to name a few.