MicrosoftTechnical development used to be about adding specific features to software so it could perform specific tasks. Now, it seems that it is about making it easy for people who have no basic understanding of the technology involved to use the software. Companies sell more product that way. That's why any of the desktop applications, be they Outlook 2016, 2019, or 365, are likely to be used differently than outlook.com, or any other webmail service.
The issue that is overlooked is who has control over how your email is handled. Microsoft (and others) want us to trust them to secure our data and keep our email private. If I send email that is sensitive, it is encrypted and stored on my computer, transmitted in encrypted form and received at its destination in encrypted form, only readable if the recipient has the appropriate key. That's why there needs to be different email clients for casual use and more serious use.
