I don't know if it's improved since I last tried it but the offline experience with Google Docs was not great. Web apps do require the web, and sometimes there are situations where you don't have it or are not willing to do it.
I've had no issues with offline mode. Pre-covid, I worked on a long document while on a cross-country flight and once I had WiFi again it just synced it up to Drive.
There's quite a bit of essential (to me) functionality that is not available offline though. For instance, you can't convert a sheet to PDF or XSLT. Version history is not available either.
