Do you really need air assist?

For cutting: yes, unambiguously. The jet clears smoke from the beam path, suppresses flare-ups, and is the difference between a brown sticky edge and a clean one. It is the highest-value $40–80 in the hobby.

For engraving it is situational — low air on wood, off for acrylic frost (the jet hazes it) and paper (it launches the sheet). Our settings chips state the air setting per material because the answer genuinely changes.