In the early 1950's Archerfield was a RAAF aerodrome with an all-over field. No 23 Squadron flew Mustangs from there. The grass would "cushion" a heavy landing. However if three-pointing a Mustang on a hard surfaced runway, a high hold-off would result in a bone-jarring arrival.
The only problem with landing on grass in a Mustang was it was easy to skid the wheels when applying the brakes (no anti-skid) especially if the grass was wet with dew. Loose grass and seeds could also be blown into the coolant and oil cooler radiators.
Landing on grass (such as present day Point Cook) is useful when training ab-initio students on circuits. Any drift at touchdown on grass, whether pilot induced or wind, meant no sideways squealing of tyres as on a runway. Also less sideways strain on the undercarriage, less instructor stress and as the student wouldn't recognise a slightly sideways touch down anyway, he maintained his confidence.