Symbolism, Imagery, Allegory
In contrast to his painful experiences in Budapest, Italy is a delight for the comrade. He finds the country "beautiful" (2) and the people "all kind" (2), and he also appreciates the art (minus Mantegna, of course). What's important, though, isn't so much that the comrade takes pleasure in his experiences in Italy, but that he delights despite how terrible the war has been for him. As much as political turmoil has created horrific experiences for the young man, it has also created life-enhancing ones, like the opportunity to explore Italy and walk the Swiss mountains.
What Italy does symbolically, then, in the story, is adds a layer of complexity to war. It makes it not simply bad or good, but instead a nuanced experience. Sure, a little art may not be proportionally wonderful to the horrors the young man has experienced, but it has made enough of an impression on him that he has purchased reproductions, which he carries with him. You know, just like the physical and emotional scars of war.