Those are neither spotting drills nor center drills. They are just an early style of carbide drills for cnc machines that can peck drill and flood coolant to evacuate the chips very quickly. The have be largely supplanted over the years by new geometries of carbide drills that actually have a twist and thru coolant(some of that type have thru coolant) as the manufacturing techniques for carbide have improved.
They work of on drilling steel plate less than say 2 diameters of the drill on a manual machine as chip evacuation isn't critical at such shallow depths. I still wouldn't do it in a manual machine as carbide being as brittle as it is apt to grenade when things go wrong. I have replace several windows in CNC HMC's when the drills exploded. One large drill, 1.125 diameter, one chunk actually went completely thru the laminated safety glass and hit the machine across the isle leaving a dent in it.
