@Jennie131 I know that's a lengthy thread to read through, but the various digressions in it offer a summary of pretty much all the hundreds of threads on this topic.
More directly to your question, obviously this system is not helpful or beneficial to hosts or guests - but it's not meant to be. So the real question is, how is it beneficial to Airbnb as a company?
A few ways it benefits their bottom line:
1) Hosts are manipulated with both with carrots (Superhost badge, appropriately orange) and sticks (threats to delist) into subservience to their listing service, often overperforming for their price point at their own expense.
2) Hosts are kept so fearful about imperfect ratings that they act against their own interests to appease bad guests. Airbnb saves money every time bookings aren't terminated for rule violations, and damage claims aren't filed.
3) The dynamic sets up a subtle social pressure that inflates the rating scores, in effect overvaluing the quality of Airbnb's inventory.
I would also prefer a simple thumbs up/down instead of all this, but star ratings generate thicker reams of data, and when you aggregate enough data it's a sellable commodity in itself.