You can also create a Google Account using a non-Google e-mail address, without any special Google Business thing. I did. I keep a Google account tied to my wor

You can also create a Google Account using a non-Google e-mail address, without any special Google Business thing. I did. I keep a Google account tied to my work e-mail address, but there is no Gmail account associated with this Google account. I can use Google services, but all my mail is on our corporate servers. A lot of people in corporations set things up without necessarily understanding what they're setting up. This includes apps. If you're thinking, "Wouldn't Microsoft know how to set things up correctly?" the answer is "Not necessarily". It's not "Microsoft" setting up some app account, it's a random guy on a random team somewhere in Microsoft, who might not have ever published an app before, much less gotten any training or done much investigation into it.