Integrating a Derivative Function (Half of FTC) - Expii

One of the fundamental theorems of calculus deals with the integration of derivative functions. For reasonably nice functions \(f\), we have \(\int_a^b f'(x)\,dx = f(b)-f(a)\). (What are the units?) Intuitively, the accumulation of (instantaneous) growth or change is just the net (total) growth or change! Why might this be useful?.