The engineer in me says that it would be a great idea to have one on my P500. It's in now, but waiting on warm weather to install.
Seems like there's always something to engineer into a simple component.
For pitch axis, it would be nicer to have an inclinometer labeled in 'percent grade' instead of 'degrees'.
I don't know what the convention is for roll axis (side slope). I get a bit cowardly with side slopes, particularly with passengers onboard.
But, in the name of "engineering", I've added illumination since the buggy was last out.
Here's an example without illumination on a mildly-overcast day:
(Not my You-tube account)
This was just outside of the Devil Anse ATV resort at H-M WV, off the resort-access trail. The "official" trails we rode on that trip rarely had a slope with much more than 25% grade, maybe hit 30% in one spot (14 to 17 degrees). We were riding alone, so we stayed on the "easy" and "moderate" trails.