However, now what do you sign into your Android device with? Google's products work... poorly... across multiple accounts. I needed to change my email address a number of years ago, which is impossible with Google's apparent use of email addresses as a primary key or something, and my Google account has had to live in a very messy state ever since... the old address has to be the core of the account for all services, even if I'm handing out and sending as a new address... and that account is an extra security vector into it... (Meanwhile, Microsoft just lets you add and remove email addresses from your Microsoft account, including changing and removing the primary.)