Indeed. I consider "gender" even sillier - e.g. Facebook adding 100s of different genders to their website - how about just removing the field altogether? Same about "legal sex" - why would the government care in the first place?! (Doctors might, but the rest of the government, not really.)
I can see wanting to know what pronouns someone uses so you can autogenerate reasonable sentences about that person (i.e. "Tomp marked himself safe from the rabid bears in Honolulu")
Phone, email, messenger, basically any collaboration software? My university assigned email addresses by initials - e.g. if you name was John Anderson Smith and you were the 167th person with the initials JAS, you'd be jas167@example.edu. Which is easier to find, search, and read in a contact list - John Smith or jas167?
Hello X near the content you're looking for is a confirmation that you're logged in; without having to look at the header (which is usually more explicit). Having a friendly name there is an attempt to use less space.
When I'm looking at my contacts in Google Docs or Slack or whatever it's critical to have the names there. If it was bigchungus12@gmail.com and db23423@exxon.com it would be very annoying.