If you want to use a scan-to-email device or other application that requires an SMTP gateway, Office 365 can be used.
In our tests, a live account must be configured for the device, otherwise you have to use a user's credentials to send mail, which may not be desirable.
We have successfully configured a number of devices, such as Canon MFP, Konica Minolta Bizhub copiers etc with these settings.