As an Italian resident you should buy an Interrail pass, but if you have a non-European passport, no-one will ask any questions if you buy a Eurail pass. It is up to your conscience if you buy a Eurail pass. 

Thank you for your quick reply.

The website of Eurail/Interrail vaguely suggested that I have a choice to buy an Eurail pass or Interrail pass if I am a non-European with residence permit within Europe. That's how I got confused.

"An Interrail Pass can be used by European citizens. Non-European citizens can use a Eurail Pass instead.

If you’re not a European citizen, but a resident of Europe, you can also use an Interrail Pass."

I see your confusion. I guess this means that you are fine travelling with a Eurail pass.

I don't know if there is a difference in price between Interrail and Eurail passes, but from a travel point of view, the Eurail pass is better as you don't have to bother about the Outbound/Inbound rule. 

I guess the prices are almost the same, thanks for your answers! I would buy an EUrail pass in this case!!

In the PAST EUrail was much more costly-and also for those after junior=>26 ONLY as 1st cl-and they were never valid in UK. But about 3 yrs ago this was all made same.

In fact someone with EURopean passpt who lives f.e. in Nihon=Japan, can buy EUrail and thus tour its own country (f.e. to see the family spread around), but this will often lead to searches and questions.

In fact-even more strange: some people from GB-railfans, trainbashers (they want to ride the whole system in UK) have been known to settle for 6 monthes ´on the continent´ and then have proof to use InterRail for much, much less as it would cost when buying tickets in UK.

Kon nichi wa!