The soft coating wears off, but I’ve not heard of anyone rubbing through the plate, so there is little reason to spread out the wear. I’m sure it’s easier/cheaper/faster to let the nozzle cut through the coating than to mask it off during production.
Also never heard of needing to replace a steel nozzle, hardened or stainless, because the tip is worn by wiping.
Nozzles (and plates) are consumables. Nozzles can be bent, or clogged, or worn by abrasive filaments. The Bambu nozzles are much longer lasting than the brass nozzles used on most other printers, and the price is reasonable.