It means that it is de-facto compatible with all operating systems.

Also means that the tooling to make collaborative work in this suite possible already exists because it's a common use case on the web and less so on native software (see Microsoft Office vs. Microsoft 365 online).

Managing documents on the back end can be very sensible, depending on your work context. Not having to deal with installations is also a real advantage in a heterogeneous environment with a mix of US-controlled operating systems and unencumbered OSes. It also makes migration between them easier, since you only need a common browser to be supported.

There are definitely some benefits! Installation and updates become trivial. Also, collaboration is generally easier, because all you have to do is send a link.

These are the same reasons Google Docs took off, and they are real advantages.