It works fine for most use cases, but Google Docs and Sheets features pale in comparison full desktop base apps.
google docs and sheets have 99% of the features that an average home user would want to use for a word processor and a spreadsheet.
The things that docs don't have are things like templated designs, and other typesetting features that a professional document creator would want to use. It also isn't completely compatible with office document formats (some formatting and alignments are wrong). I would imagine similar with spreadsheets.
Until you get to multiplayer document editing.
Having multiple people working literally at the same time is an interesting way to work, though not something I want to repeat/rely on often.
Uhm. You probably haven't seen the crazy Google sheets that exist out there.
They are really stretching what you should be doing with a spreadsheet and they are fully collaborative/multi-user. At some point it got really old to wait fifteen minutes for the sheets to recalculate.