Like many others, the first time I read it years ago, I picked up pretty much only on the time-management stuff, and I was looking for a quick solution, so I missed some of the main points. Having read it recently again, I got so much more from it! It's funny how we can filter data out when we aren't ready to face something, change our attitude, etc.What I like is that Covey's underyling idea is that there is an ethical natural law that you violate at your peril - and that you can profit from if you follow it. But it's not about "success", it's more about living a life based on unshakable principles that can sustain you, no matter the circumstances. It will also shield you from just reacting to what is thrown at you and mechanically going this or that way. He defines free will as that short moment between stimulus and your reaction - this is where it's at!
The message reminds me a lot of Jordan Peterson. But Covey doesn't go into science or religion, he rather focusses on practical advice and on bringing his core messages home. It had a big effect on me and I now often think about things in terms of "I decide to do this or that" instead of just being thrown around by circumstances. This shift in mindset alone can be such a blessing! There's so much more in the book, and I think everyone can get a lot out of it, whether you have time management problems or not.
With the Work in mind, reading it is quite interesting, like Luc explained above. I guess it comes down to it being a practical way to focus on our core values, on long term goals, and most of all, on being as aware as possible and not going into black&white thinking, emotional thinking, etc. Some of his suggestions are really making a difference for me at least. I feel, like he said, that changing is not so scary when you know that there is an unchangeable core that you value more than "success", keeping your thinking errors and narratives, etc.
It's also refreshing to have a book on this topic that focuses on real stuff (not fake values as promoted by society today), and encouraging people to take responsibility and act more consciously, instead of the more common "self-help books" where all you get is a promotion of fake niceties, fake success and egotism, mixed with a bunch of self-pity, "you're speshul", "hug your inner child", etc.