Handicapping is routine in the Japanese game Go (my best game). The basic strength unit is one stone, and a one-stone difference represents a full level of difference in strength.
I (about a 1500 player) once asked a 2100 player how much of a handicap she would need to give me so that we would have an equal chance to win. "Probably a knight, maybe more," she answered. I once took a knight handicap against a 2200 player and lost, but it was a much tighter, closer game than one with no handicap.
That might suggest that a pawn is equivalent to about 200 points of rating. Apparently handicapping doesn't do much for say, a 50 point difference in strength (you just play and take your chances). But above that, there might be ways to use handicaps. Even giving someone the first move two times out of three (as was earlier done in professional Go) might do something.
Or would it? Why hasn't handicapping been done much formally in chess, as in Go?