SES' documentation recommends using Punycode for local domain - why?

As per this SES documentation https://docs.aws.amazon.com/ses/latest/dg/send-email-raw.html:

For example, to send an email to 张伟@example.com, use Punycode encoding on the local part of the address (the part before the @ sign). The resulting, encoded address is xn--cpqy30b@example.com.

I just tested this on gmail, and unless I did something incorrectly, Gmail seems to just show the ASCII characters - I suspect most email providers will do the same base on the information I found here: https://stackoverflow.com/questions/7497468/can-punycode-encoded-email-addresses-clash-with-real-addresses

Am I missing something or should there be a warning in that document and maybe even a better recommendation to convert to ASCII instead?