I don’t know about sharing passwords, but I know that if you have an Exchange server on premises (meaning you have mailserver on your own infrastructure maybe somewhere in the building) because you don’t want to have your data in the cloud - Outlook for mobile (both iOS and Android versions) has been sending all your data through M$ servers anyway, don’t know for how long - quick search returned a 3 year old reference - imo much longer. There are “benefits” that I may be too dumb to understand:
On iOS you can go around and use the default “Mail.app”. On Android I haven’t found a good app that would work with EWS - I’m using K-9 over IMAP which isn’t great.