Ichigo,
Don't be discouraged, remember that at one time or another almost every North American Species was thought to be inferior to the established "Eastern" species. Japanese Black Pine was and still is thought by many to be a superior species for bonsai, but it really isn't, compared to other pines, I personally think the fascination with this species comes from the sole fact that the Japanese used it. However, one must consider that they did not have a wide range of material to choose from, the tree was native, easily accessible at the time, and there were plenty of old trees in nature to collect..
As artists work with new species, new techniques are developed that work well with that particular species, bonsai is still growing and we see many new species being used all the time.
But, as Brent pointed out, a beginner may well be better served learning on species that have a established track record and plenty of documentation to guide them.
We can be sure that quality examples of Hollywood Junipers will be shown in the future. At one time Eastern Red Cedar was thought to be a junk tree, but now we are seeing examples of excellent bonsai created with this species, the same can be said of other species thought as junk.
Bonsai, as an art, is not limited by the material, but only by the imagination and talent of the artist.
Will