I have also heard that some firms ban its use.

Why?

Because it makes it SO easy to set up a database for your app that you end up with a super critical component of your application that looks exactly like a file. A file that can have any extension. And that file can be copied around to other servers. Even if there is PII in that file. Multiply this times the number of applications in your firm and you can see how this could get a little nuts.

DevOps and DBA teams would prefer that the database be a big, heavy iron thing that is very obviously a database server. And when you connect to it, that's also very obvious etc etc.

I still love SQLite though.

The specification is publicly available

- It is widely adopted - It is likely to remain readable in the future - It has little dependency on specific operating systems or services - It carries low patent risk

From the perspective of long-term continuity, avoiding dependence on any particular company or service is extremely important.