What AT&T and Verizon are rolling out are not real 5G. They're more enhanced 4G. China is planning to build a completely separate 5G network, which is going to be much faster, indeed up to 100x faster than the current 4G network.
The former approach is more cost effective in the short term. Chinese approach is more expensive, clearly.
Yes. Until you get a real 5G network, you don't get the benefits of minimal network latency and rock solid reliability, which is what will power new applications.