A screen protector takes the scratches and cracks before they reach the iPad Air (2020) / Air 4 display. A broken protector costs a few francs to replace; a cracked original display costs many times more.
Look for full glue: the adhesive covers the whole surface, not just the edge, so corners don't lift and no rainbow patches form. 9H hardness resists keys and sand. For the iPad Air (2020) / Air 4 the glass fits precisely with cutouts for Face ID and the earpiece.
To protect the cameras too, pair the screen glass with a separate lens protector.
The iPad Air (2020) is the first non-Pro iPad with USB-C, Pencil 2 and Magic Keyboard — LED Liquid Retina 10.9″, A14 Bionic chip and USB-C. A good case protects the display and the aluminium back from scratches, drops and table edges, and preserves the resale value of your device.