I think the "functionally equivalent" part is quite arguable, at least it was in the past when many techies made the switch from hotmail to gmail.
People switched because the features and interface were far superior.
No one should use the web interface, let alone "techies." Use a real email client and everything behaves identically.
Even to this day, I don't know of an easy way to switch between fresh devices all the time and use a "real" email client.
I don't see the problem with someone preferring gmail - personally the +suffix tagging was what I still use to this day.