Using Google Sheets as Database?

What are your use cases for this? Who/What will consume it?

I did not used Google Sheet as Database and I dont see it as a good option for connecting to it via a programming language when taking into consideration any RDBMS or NoSQL if that is needed.

I recommend either PostgreSQL or MongoDB or Cassandra.

Elaborate on the use case? Why Google Sheets specifically, not some online simple DB with a rest API?

It reminded me this - https://www.bbc.com/news/technology-54423988. Sheets are not databases. Be prepared to hit one the issues like this.