You don't have to be a tree hugger to benefit from the approach in this book. The savings the authors recommend can come from lots of different places: housing, clothes, travel, food, entertainment, having or not having kids, depending on where you start and what is important to you. You might decide that you like living on rice and beans but have to go on a cruise every year. You might go to restaurants a lot, but bike instead of driving and live in a tiny house. In fact, you could decide that you like being a money-hungry yuppie just fine, and increase your consumption instead of cutting it. Or you might ditch your idealistic, low-paying job and get a higher-stress, higher-paying one to reach your goal of financial independence. The good thing is, the book offers a step-by-step plan to help you decide. Even if you like working and are not aiming for early retirement, you can still use the exercises in the book to prioritize spending and savings.
The weakness of the book is that the authors show their own biases too much. The ultimate goal in their view is to move from the city to a small town, quit working for pay entirely, and do volunteer work instead. This is not everybody's cup of tea, and some of the penny-pinching suggestions in the book (having potlucks instead of dinner parties, spending your vacation in your own hard-earned home, buying food in bulk) may seem tacky and depressing. Don't be put off, though: you can still benefit from the financial plan they describe even if you don't share their preferences and goals.