The point is that English is the de-facto single working language of the EU, and the de-facto business and scientific language of Europe, and so it might as well be made official.

If countries offered Government services including education in English, it would hugely assist the movement of people and capital throughout the continent.

Consider: you are from Spain, and have been offered a job at a great company in Germany. You will speak English at the office and probably get around the city speaking English. But: your children need to learn German, fluently and immediately, in order to continue their schooling?

An official EU English would help pave the way for National Governments to offer services in both the local language and English.