Why would China want to take down the dollar? Don't they own America's debt and rely on USD factory orders?
If the Chinese elite utterly destroy the Western economies, they rule the world. Simple as that.
Get used to it: The state attracts psychopaths. It's purpose is power, not wealth. Human lives mean nothing to the psychopaths on top. You, my friend, are a means, not an end. So are all the other tax serfs, everywhere.
The US and most big countries are no different to China, all hunger for power.
In China the human rights are worse or non-existent if you didn't make it in life.
That said China would rather to destroy the US from within. They are buying up bonds and land so the US owe them everything and do their bidding.
Basically the same as the US is doing in countries like Afghanistan, Irak, etc. and has done in former Soviet Russia.
Basically the same as Europe is doing with countries like Greece.
Make the bastards owe you so they do your bidding! (this is power)
You basically buy the country, liquidate it's assets and own it's land and people. The US does this by injecting pro-US governments in those countries.
Destroying a country by bombing it's economy leaves nothing useful and gains no power, just eliminates competition.