There are many uses for a small inspection camera including checking condition of pistons, cylinder walls, chamber debris and valves through the spark plug hole. Below are some other useful ways to use the camera.
Click on a pic to enlarge:

Check your belt tension without lying on the floor to see the scale on the belt guard
Camera mounted to a dial indicator magnetic base 1)	Note position of the belt in the window with no force applied 2)	Finally, the belt with 10 ft/lb applied using the belt tensioning tool 3)

This 45° mirror attachment allows you to see horizontal holes and features that are normally blocked from view as in below. 4)

Checking for debris in the oiling holes in the lifter bores. 5)