Your engine is a complex arrangement of metal
parts moving constantly.
Without oil, the friction caused from metal on metal g
generates enough heat to melt those moving parts and causes them to quickly fuse together
causing a 'seized' engine.
Without oil pressure, your engine just wouldn't survive more than a
mile, a lap, a mud hole or a stoplight.
It flows everywhere - lubricating,
cooling and removing miscellaneous dirt and debris.