The reason in the first place why there are English words in the day-to-day Italian is because a majority of the population _uses already these words_.
Given that, this goes against the "preserve communication" argument. After all, this is how Italian was born (at least that's what we studied in school), there was Greek, there was Latin, somewhere the language got distorted by common people all the way until it became Italian and got shared by many, many people.
The language was not defined, it evolved with how people used it.
This process has been going on forever, I don't see why it should change now with artificial constraints.
For what is worth, official documents should be allowed in English language for the entire country, given we are part of the EU, there is a whole money-sucking machine (and time-sucking!) to translate things in English when interacting with other EU countries.