Tempered glass protectors offer better protection to the screen of phones and tablets. This is because when the device is dropped or something hits the surface, the glass absorbs the shock and pressure. If the impact of the drop is so strong to break something, the screen protector is what is get broken.
Tempered glass protectors are also resistant to scratch. This is because of the property of tempered glass that does not allow it to be physically altered unless by application of high heat.