> I understand there are some missing features compared to the old one

There are some people that use Outlook for...well I'm not sure what but things that go way beyond email and calendar. I've been using the web app for several years now, it's fine. When I was new in IT, I always struggled to see what the big deal was with Outlook desktop. The web mail has folders, rules, shared mailbox support, integrated calendar, etc.

What more do you need out of email?

Well, turns out a lot. People treat email has a permanent data store. I've encountered folks with multiple PST files archiving 10+ years of email. I ran into people that needed to queue up a bunch of offline emails in their outbox to send when they're on network again (ok, I kind of get this use case), and I came across all manner of horrors of COM Add-ins.

Anyway, the root of the problem is people using email for everything it was never intended to do or be. If "new" Outlook can break some of those habits, we'll all be better off for it.

Public Folders is what makes us stick with the old Outlook client. For 25 years Public Folder has been a simple drag and drop, hierarchical archive system for communications with clients and vendors at team level.

Same experience when I worked somewhere using outlook.

I exclusively used the web UI because it always ran faster for me, except for a small number of things it couldn't do.

Same experience here. Web version works just fine.

Even their Office Suite runs okay in the Web. For heavy lifting, like getting an md file into our Corporate Design, I still use libreoffice combned with our template.