If you're fully immersed in the Microsoft ecosystem, going from your Outlook calendar to a Teams call is a single click, and the desktop app doesn't take as long to get into the call.
I use both and shudder every time I am forced to use the lame web app alternatives to Word, Excel & PowerPoint on desktop - mostly because my child's school runs on web alternatives. Ironically even on Android, Outlook seems to be the only major client that actually provides a unified inbox across mail accounts due to which I switched & use my Gmail accounts through it.