Both feature food tasting, cooking competition, japanese and italian dishes, a girl with big breasts, and tanned girl with big cleavage, a condescending loli, an italian guy and an old man who is the ultimate authority on food tasting.
Though one is placed in a school setting and one is placed in a restaurant, they share various similarities.
Both Animes have a duration of about 3+ Minutes.
Both Piace: "Watashi no Italian?" and "Komori-san wa Kotowarenai!" are short comedic slice of life Animes with a cute female Protagonist and her friends.
Both Animes more or less co-exist as Advertisement for the Manga Adaptions and their Spin-offs (as seen in the descriptions of each)
Both anime about restaurant customers who are eat unknown dishes of eastern and western cuisine. In Piace: Watashi no Italian customers are people, and in Isekai Shokudoucu stomers are fantastic creatures from another world.