A screen higher than the bezel (which is common these days) means that it's more likely that the glass will take the imact in a fall. However, glass is always vulnerable: my current phone does not have that, but still has a crack on the screen after a drop (onto an uneven surface, tiny chip which then developed into a crack over the next few minutes).
Gorilla glass is primarily scratch resistant (not unscratchable - it's harder than the sort of alloy that keys and coins are made from, but there are things that can scratch it). No glass is unbreakable, and in designing the glass they have to balance hardness (scratch resistance) and flexibility (shatter resistance).
As for a plastic screen protector, it will absorb a bit of impact, though it will scratch very easily compared to the glass underneath it. It won't make the screen unbreakable though - best advice is still not to drop it.