whois ycombinator.com|grep -Ei "phone|email"
Registrar Abuse Contact Email: abuse@support.gandi.net
Registrar Abuse Contact Phone: +33.170377661
This used to be a way to get contact information for domain holders but spammers have effectively squashed that concept. Phone numbers are also commonly stored in LDAP/AD databases and can be queried over DNS internally within an organization.If one were so inclined they could share their contact information in DNS in TXT records. Not many people would know to query this unless it became a standard at which point spammers would squash it there as well.
Another semi-standard domain related place people could put contact information if they were so inclined is humans.txt [1]
Landline phones are going away quickly, on mobile phones we usually just click on the address book entry. Personally, I only have to type in a number very rarely and typing in a number vs a string doesn't really make a big difference in that case.