The only benefit, and it may be a big one, is real time collaboration and document sharing.
I understand that some might see offline storage and editing as advantages, but I've only seen it create chaos. It makes the file save dialog much more complex and I constantly have non-technical users mail files around like it's the 90s because they don't understand how to share it properly.
https://www.saasgenius.com/blog/why-office-365-is-overtaking...
https://www.computerworld.com/article/3637079/as-google-move...
> Google grew its share of the productivity software market to 10.3% in 2020, according to research from Gartner, taking about 2% from Microsoft. Microsoft is still the clear leader however, with 89.2%. Overall, the productivity software suite market grew 18.2% during 2020.