Because it has more pokemon, better graphics and can connect to the global link. Tms also have unlimited uses in B/W
As far as I know, Pokemon on Pokemon Black and White have to stay on those games, as for Pokemon HeartGold and SoulSilver, you can not only migrate Pokemon from earlier generations of games, you can also trade with Pokemon Platinum and Diamond and Pearl. Still, the Pokemon on Pokemon Black and White look cooler! :)
You cant.
no
no because you cannot get Pokemon black and white Pokemon on soul silver
no it is not it is only in black and white
heartgold and soulsilver
Heart gold and Soul silver is better because most of the Pokemon in Black and white you don't know if there good or bad,but in Heart gold and Soul silver we all know Lugia and Ho-oh.
If you have Celebi on Pokemon Diamond, Pearl, Platinum, HeartGold, or SoulSilver, you can use the PokeTransfer machine in Pokemon Black and White to transfer it.
It does appear anywhere in black OR white only in platinum, soulsilver, and heartgold.
There is no HM for Dive in SoulSilver, but you can get it by transferring a Pokemon who knows dive into SoulSilver the Pal Park. but you can get dive as a HM in Pokemon black and white but not in soulsilver,heartgold,platinum,diamond,and pearl
You are unable to transfer Pokemon to previous generations, mainly because there are all new Pokemon in Black and White.
Heatmor isn't in Pokemon SoulSilver or Pokemon HeartGold. It's only available for Pokemon Black and White and Pokemon Black 2 and White 2.