Interesting to note that cloud storage and realtime collaboration isn’t 100% tied to a browser-based interface though. Even though many existing apps work like that, there are desktop clients for a bunch of cloud-native SaaS (and even though some of those are Electron).
Regular desktop Excel supports multi user collaboration on workbooks saved in onedrive exactly the same as excel online/Google sheets etc do. You can see what other users are working on and their changes are synced instantly. The only annoyance is when one user changes a filter and it changes for everyone.
