Who cares?
Edit: to be less glib bc I am trying to be nicer, creditors dont have leverage over debtors with options. Reserve currency = options. We can sell treasuries elsewhere.
Also if China stops using treasuries to manipulate their way to USD scarcity and RMB devaluation, ESPECIALLY in context of full on trade war with US, it would quite literally destroy the Chinese economy.
We have them by the balls if we are willing to suffer short term pain. We are, however, likely not willing to do so despite Saz's optimism.