Comments in Salesforce contact email address

According to https://help.salesforce.com/articleView?id=000321158&type=1&language=en_US&mode=1, Salesforce supports comments in email addresses

Comments – denoted by matched parentheses – are allowed in the domain
as well as in the local-part. Comments in an email address are ignored
when sending email; for example, john.doe@(comment)example.com, and
[email protected](comment) are both equivalent to
[email protected].

This does not seem to be the case as this procedure can be seen failing with the error "You have entered an invalid format." on the following screenshot(here I am assigning this email address to a Contact):

This example was copy-pasted straight from the Salesforce help article, so it should be sufficient to demonstrate the inoperability of this functionality. I also tested placing comments before the @ and after the @ and before the domain name — all options failed.

I understand that this functionality is quite niche and largely more weird and unintuitive than helpful, however I believe it would help me solve an on-going production issue, so I’m a bit baffled as to how this RFC approved format seems to not be accepted in this field.