There can be no hard done by displaying your e-mail address to others but many users don’t want their e-mail address to be visible for privacy reasons.
Before this is a user wanted to hide the account information on the login screen one had to use Group policy or Registry editor.
Hiding account details on Windows 10 login screen
Microsoft has now provided the options for users to either show or hide the email address according to their need which can be done in settings. This is only available for user who are using Windows 10 14328 or above.
Show or hide email address on sign-in screen in Windows 10
Step 1: Open Settings but either accessing it through the start menu or pressing the Windows logo + I.
Step 2: Go to Accounts > Sign-in options.
Step 3: Under the Privacy heading there will be a switch Show account details (e.g email address) on sign in screen, turn it off to hide all the details when signing into your Microsoft account.