The benefits are over 20 pages of exercises in one book alone. You'll also be able to apply each exercise to all keys (transposition).
The cons are this is not a quick fix. It may take some time to see improvement. It can get repetitive and boring. The exercises are in "fixed" positions, meaning you won't be playing beyond an octave (most of the time). There's also no concrete, scientific evidence it's even worth it to practice these exercises. And you might also become too "mechanical" in your playing.
If you're going to use this book, my advice is to make sure this is just a supplement to your main technique practice. You should also be doing scales, arpeggios, etudes and ear training. With so many finger independence exercises to choose from, you really only need to stick to a few at a time. You can also randomly flip to a page and practice whatever's on there as well. Practicing your non-dominant hand (left hand for right handers, right hand for left handers) specifically. Lastly, make sure to practice musically (phrasing, dynamics).
Book 1 ?https://amzn.to/2wfQjn4
Book 2 ?https://amzn.to/2MWCTUg