What are reasons not to use Deno in production? When do I know Deno is mature for production?

When do I know Deno is mature for production?

In my opinion there are two ways to tackle this:

1. Wait for others to try things and follow their opinions/results
2. Write some things yourself, write tests, deploy it in some dev-scope and see for yourself if it withstands your standards. Based on the results you can form your opinion and compare it to the other options out there