On a winter morning in 2013, an asteroid about 20 meters wide burst over Chelyabinsk, Russia. The flash drew people toward windows; the pressure wave arrived later and shattered glass, injuring around 1,500 people.
YR4 is estimated to be roughly three times wider. Because mass grows much faster than width, that difference matters. It helps explain why astronomers treated the earlier Earth-impact probability seriously and why the 2032 flyby remains such a valuable chance to study an object in this size class.
Chelyabinsk also shows how different observing circumstances can be. It arrived from near the Sun’s direction with little warning. YR4 was found years ahead, giving observatories repeated chances to measure its path before it comes through the Earth–Moon neighborhood. Same solar system, dramatically different views from Earth.