Actual sense in buying rail pass a lot depends on countries where you plan to travel and kind of intended journeys there. And the reason why we usually say "don't buy the Pass" is because fellow travelers consider pass for either very few journeys, or plan to use it in the region where majority of their rail journey would cost less than the price of the pass travel day. While with lengthy itineraries in relatively "expensive" rail countries (=almost all the Western Europe) pass quite often is hard to beat. Your case seems to be like that.
The only comment we may have looking at your plan is that maybe it would be more economical to manage the whole thing with 21 days pass. Why? Because your first days in Italy can be easily and cheaply cover with smartly bought point-to-point tickets, while your last days in Sweden aren't full with many rail trips, so something like Stockholm-Uppsala you can as well travel with point-to-point. So at the end the sum of your point-to-point tickets* can be less than difference between the price of 30 and 21 days passes (although to confirm this guess we may need to know the exact difference in EUR, because in the
Eurail Pass website we doesn't seem to find your 770 euro option)
* e.g. Rome to Florence is easily doable with 9 euro ticket, Florence to Siena even before departure is just 8,7 euro, Milan to Lugano can be done in <10 euro and so on.