Next, why we should adopt a web-based Outlook, if made great, no such fail as electron based Teams or previous Edge.
If you are using IMAP and Exchange Online the performance you get is better (usually) as you don't need any Caching in Ost or PST files.
It works with lesser storage footprint in Windows 365, Windows 11, especially non persistant scenarios, such as RDSH, FSlogix, Citrix and AVD.
Outlook legacy App uses stuff reaching back to MSMAPI and roots in NT4 Windows check registry.
It's so old stuff they refused to implement the Outlook CPL (the only not visible via indexing) it into settings app even though Windows Insiders, including me asked for it since October 2015.
So I appreciate much project Spartan and cutting of filthy braids, and technical debts.
It's sad there is generally more complains than appreciation of the good "Outlook" on Outlook's future.
It's like with Edge. People will learn it's a great product if they get used to everything new and improving their daily life. Even it's not :hundred_points: percent for all users at release.