I mean... You can open Office documents in the browser, but for anything beyond basic tasks it's not even close.
recent only office builds are not quite there, but far superior to office Web.
Subscription-based licensing requires periodic check-ins, but perpetual product key-based licensing is available, though compared to the subscription versions, the release cadence for new features is slow.
The online component of traditional apps like Excel works best as a means for sharing documents, with the web UIs useful for reading and light editing, and the same documents fully editable in the native apps.