Good for climb performance, glide, lift reserve comfort, descent speed, etc., etc.
I have used this tool along with other tools (altimeter, turn coordinator, VSI, attitude gyro, DG, compass, airspeed, etc) when appropriate and as needed - sometimes I look out the window as a cross check.
Scott Krueger AKA Grayhawk
Lancair N92EX IO320 CS Prop
Slow Build 1989, Flown 1996
Aurora, IL (KARR)
Eschew Obfuscation!