A protector will slow down the rate at which an oily or aqueous spillage is absorbed into the fibre, so it gives you more time to take appropriate action.
Small splashes and spills can easily dry out before they are absorbed making removal very easy.
Dry soil finds it more difficult to bind with protected fibres so is more easily vacuumed away.
A quality protector on your carpet or fabric, treated correctly will withstand at least 2 cleans before requiring a top-up
Safe and happy protecting
The Ken