Google is a lot of things, but one thing they are not is bad at managing email.
And you'd be surprised at the number of "professional" emails you get, which are actually @gmail. Because "sites" allows you to use gmail accounts to represent non-gmail addresses. In that way, you have spam protection, filtering, searching, all the stuff Google knows how to do, without the supposed stigma of an @gmail address.
If you want to complain about something, notice how Jared Kushner is using WhatsApp for White House communications, which is maybe .000000004 percent as secure as Hillary's emails, which got the minority party in this country into a tizzy.