Sensitivity is an important microphone spec, but its relationship to a mic's performance is not always well-understood. Other specs, such as SNR and THD, better describe a mic's performance, but that doesn't mean that sensitivity isn't important. A designer needs the microphone's sensitivity spec to properly design the system's gain staging by maximizing signal levels and avoiding clipping.
Now that MEMS microphones are available with a variety of analog and digital output formats, comparing the sensitivity of a mic with one type of output to one with a different output is not straightforward. All mics, whether analog or digital, share a common measurement unit of measure in the acoustic domain, SPL. Using the acoustic domain makes it easier to directly compare the signal levels output from different microphones.
You can learn more about a microphone's sensitivity spec and how to best use that in a system design in this month's Analog Dialogue Back Burner article called Understanding Microphone Sensitivity.
I welcome any feedback or question on this article, or any other microphone topics, in the comments below. I hope that this article is helpful to better understand microphone sensitivity and how it applies to system design.