Its to show you I spend all day fixing the mistakes of people that feel they know how to take care of their cars paint but have no idea what they are talking about. I hear all the time "I only take it to a brushless car wash. While better then a car wash that uses brushes the high pressure and strong chemicals arent good either. Like I said, Its just my advice. Do as you like.
How does it protect against acid spots from sap, bird crap and bugs? Because dirt, dust and water spots can all be washed, polished or buffed out but acid spots really do a number on your clear coat.
Its harder then your clear coat so it takes longer for the acid to etch into your paint, It also cant stick to it as well making it easier to clean. That doesnt mean you can leave it for ever. You should still clean it off as soon as possible.