Why so popular? The picture below is why people plant them. Beautiful red fall color. The 'Red Sunset' Maple is one of the most commonly planted trees.
Here is another shot of a fairly typical specimen, but its in full bloom.
Fruit is a pair of winged samaras, small .75" long with 60 degrees between the wings. Mature very early, usually red in color and fall by early summer.
Misidentification? Other maples perhaps. If you encounter one of the columnar forms of A x freemanii you might think its a silver maple only because of the leaf.
Santa Cruz : 931 Mission Blvd. are a pair or decent looking ones.
Pleasure Point: 558 35th
Scotts Valley : Mt Herman Rd at the shopping mall at the CVS/McDonalds end by the road. These are columnar forms, most likely 'Armstrong'.