Axle ratings are solely the weight suspension/axles are rated to carry. You meet GAWR so you don't overload the suspension at either end.

Vehicle weight ratings include meeting acceleration, handling, and braking goals. You meet GVWR so the vehicle retains the handling characteristic specified by the mfg.

For those thinking it already, yes, there are NHTSA minimums, I stated mfg spec because they exceed the minimums.