These bits are designed to drill flat bottom blind holes for European style hinges.
Flat bottom boring bits are also used for drilling large diameter thru-holes without the plug that is typical when using a hole saw.
These thru-hole bits are used for locks, door knobs, wiring holes, etc. Flat bottom boring bits are designed for use in wood or plastics and are not intended for use in steel. For best effect, use with a drill press, if at all possible. You can accurately set the depth of cut and keep it perpendicular to the panel.