Money titles tend to promise either wealth or peace of mind. The Cashflow Compass promises direction, which is both a more modest pitch and a more useful one, and it is the work that brings Elijah D. Porter to our money and finance shelf.
The metaphor is doing the explaining. A compass orients rather than instructs, which sets the expectation of guidance rather than of formula, and cashflow rather than investment narrows the ground further still: this is about money as it moves, week to week.