Why is a learning the Beijing dialect important?

[aquadraht]

You seem to have misunderstood the bit about "Beijing dialect". There are roughly 7 languages in China, called "dialects", one of them, the most used one, is the Northern Chinese Mandarin 'dialect', which is also spoken in Beijing (I abstain from detailing about the other 6 here). A standardized form of the Mandarin dialect is used as the common Chinese spoken language, 普通话. Within all of those 7 languages, there are local tongues (or real dialects). Chengdu, like Xi'An, is within the Mandarin (普通话) zone, yet Chengdu local tongue widely differs from Beijing's or Xi'An's.

One may argue whether Beijing Chinese is the best or purest 普通话, the excessive use of 儿 and other features stand against that perception. I heard that best 普通话 is spoken in Yilin, but you'll hardly find China's best language schools up there.

Maybe it is bit easier for you to learn Chinese when the locals are not speaking Wu, Hakka, or Cantonese. Maybe rather not, because you might adopt the locals' customs dealing with their mother tongue - Cantonese, Tibetans, or Uighurs may speak a more school-like Mandarine than e.g. Beijingers.

So the choice is up to you. Good luck.

a^2