Beware of Ryanair's online checkin system

I booked a Ryanair flight to Italy a month ago. By paying a bit more money (4 pounds), I opted for online check-in (and priority boarding).

Two days before the departure, I got email reminding me of the online check-in.

Then I realized that the online check-in system is only available for passengers with an European passport who are NOT travelling from Italy to UK.

Well, I still enjoy the priority boarding, but I feel like I was cheated...