Solid proof that the source of all life on this planet actually began on a different world. The critical components came here via a comet or even an spacecraft that inadvertently dropped it off. Should screw with a lot of ideals
This is always my reaction to this theory as well. If someone asks "How did life on Earth start?", surely we can assume they actually mean "How did life start?"
It's like if a kid saw a baby, and asks their parents "Where do babies come from?", and their reply is "Oh that baby lives next door, it came from that house".