Pottinger is the latest in a long tradition of American figures who believe that they can reach out directly to the East and convert them. Some have succeeded in the past, most have ended up in the historically irrelevant trash heap. The sheer irony of having a member of the current administration preach about liberal values and "a little less nationalism, a little more populism" leaves me with little doubt on where Pottinger will find himself 50 years from now.
If Pottinger's goal was to "cut through the noise" and "open up a conversation" directly with the Chinese, the reality was that a very limited audience of elites was listening. That elite audience understands English and certainly doesn't need to put up with a gimmicky Chinese performance. And they certainly don't need to listen to an American pontificate about Chinese history and culture.
If Pottinger's goal was to reach out to the Chinese liberals and give their cause for reforms a boost, the reality is that he made their life more difficult. The liberals/doves in China are already marginalised and drowned out by the hawks, who will see Pottinger's speech as nothing other than interference in domestic politics. Those who use Pottinger's speech to call for more domestic reforms will simply be labelled traitors. There is a Chinese term for this, i.e. 弄巧成拙.
In summary, I think we have overstated the significance and impact of Pottinger's speech. But it's fine because he probably got a whole bunch of pats on the back and praises from the DC echo chamber, and that's what really matters right?