I think that is a reason the catholic Church still uses it for things like papal encyclicals. It puts different groups on a more equal footing.

Far more people understand it than things like Esperanto. Quite a lot of people know it a bit. I did it at school. My kids learned some (their choice to do it up to GCSE level).

That said, in practice, English is the international language. It is what is most likely to be used at an international conference in most fields, or when people with two different native languages speak.

The EU has already started expanding to countries whose prestigious classical language was Greek, not Latin, so Latin would no longer look like a compromise but favoritism towards Western Europe.

Or Esperanto. But Spanish or Italian would also be great as they sound so nice.

> Latin language should be become the official language of the EU

It would be more practical, if everyone spoke the same language, but the EU does deliberately not want that. The EU wants to preserve language and culture of its member states and regions. "United in Diversity" is an important idea of the EU.