Overview
Pillows seem optional until a bad one keeps waking you up every time you roll over.
The Fillo works because it is not trying to be only an ultralight air pillow. NEMO uses a baffled air cell for shape, a foam layer for the soft top feel, a removable machine-washable cover, and an internal stuff sack that cannot get separated from the pillow.
The current Fillo is listed at 9.2 oz minimum weight, 9.3 oz packed weight, 17 x 11 x 4.0 in dimensions, and a 6.0 x 4.0 in packed size. That is not nothing in a backpack, but it is a reasonable trade when sleep quality matters more than shaving every small comfort item.
The trick is not to inflate it until it becomes a brick. Slightly under-filled is where the foam layer and air chamber work together instead of turning into a bouncy balloon.
This is not the lightest pillow move. It is the sleep-better move.