Don't know why people are buying adapter, the Uniden supplied adapter has been working for me for weeks.
The Uniden adapter works. The one I've been selling is easier to grasp when attaching or removing an antenna, and provides more support, so that the SMA connector is less likely to break if a sideways/bending force is applied to the antenna (like if you drop the scanner). Some people find those features to be worth the cost, others do not. Everyone is free to choose either way.