We have a UK client in the healthcare industry who registered the domain clientname.healthcare, and they rapidly found that the NHS imposed regexes which rejected name@clientname.healthcare emails.
Aside from regexes though, I also think the new TLDs confuse quite a lot of people. name@clientname.healthcare just doesn't click as an email address as quickly as name@clientname.com, and I'm in tech so I'm sure it's much more confusing for people outside that space.
In fact, that reminds me that we built a site for another client for use inside an exhibition space which was spacename.house and against our advice they put that - without www or https:// - on exhibition panels for use on mobile phones. I am absolutely convinced that most people didn't realise it was a web address.
For years I've had a catch-all subdomain to give out addresses like company@sub.domain.tld which makes filtering out the junk when companies invariably sell their email lists or get hacked much easier. It is getting rarer, but I still occasionally run into sign-on forms that don't allow more than one “.” after the @ unless it is due to a recognised two-part country suffix like .co.uk.
I would never use something that isn't a country TLD for email for this reason, I assume there are a lot of bad systems out there that will incorrectly see them as incorrect.
Aside from regexes though, I also think the new TLDs confuse quite a lot of people. name@clientname.healthcare just doesn't click as an email address as quickly as name@clientname.com, and I'm in tech so I'm sure it's much more confusing for people outside that space.
In fact, that reminds me that we built a site for another client for use inside an exhibition space which was spacename.house and against our advice they put that - without www or https:// - on exhibition panels for use on mobile phones. I am absolutely convinced that most people didn't realise it was a web address.