Actually, it isn’t so.
Mascarpone is a creamy and sweet cheese which is extensively used to make sweet desserts (Tiramisù, for example). Its use in main courses recipes is quite recent and not so common. I think (but I can be wrong) that the recipe you cited comes from the nineties.
I’m sure I have eaten it at some friend’s place once, but I’ve never seen any mascarpone-based pasta or main course in any restaurant. I invite other italians to correct me, if I’m wrong.
I can add that often, in addition to eggs in carbonara, another creamy ingredient which can be frequently mistaken for cream is besciamella, which is used in lasagne, cannelloni, crespelle.
Most of the “creamy” italian recipes doesn’t contain any cream: if made “all’onda” (wave style), risotto can be very creamy too. Cooking rice releases its starch, and after cooking you make a procedure called “creaming” which involves only butter: it mixes with starch and gives risotto its creamy look, which is achieved with a very little amount of butter. So risotto can be very creamy, in spite of its very low content in fat.
PS: where are you from? I don’t know why, but I used to believe you were italian, too…
EDIT: I asked my wife if she remembered any mascarpone recipe in restaurants… she (who didn’t read the thread) told me: “I’ve never read it on menus, but I’d bet that some low-level restaurants trick their risotto with cream or even mascarpone!”