All other things being equal (materials) they
can move faster and track transients better
but since they lack the surface area of a 12"
move less air - which is why they get coupled
in arrays (2x10 4x10 etc so often)
They also exhibit less "beaming" than a 12"
(directional projection or narrowing of
the sweet spot) since this is a function of
wavelength vs, diameter of the cone...One
of the reasons the higher the freq a speaker
works for, the narrower the driving surface.
(tweeters being 1 inch or so and woofers
starting at 6 inches on out to 18' in general.
"Smoother"? Many factors can effect perceived
freq response but for my money it is the