Absolute measurements are generally used in applications where you need a repeatable reference pressure; i.e. in an experiment or in a barometric application. For example, if you are looking to replicate a test that was originally completed by a colleague in Denver, CO and you are at a facility in Boston. May you may want to use an absolute sensor to minimize variables in your test. Other applications include weather stations, altimeter calibration equipment, and semiconductor fabs and many more. However, if you want to measure or control a pressure that is based on current conditions a gauge sensor may be best.