Due to regulatory requirements (EU Digital Markets Act and similar laws), Microsoft is required to publicly display the following information on every app's Store page: the publisher's name, address, email address, and phone number. For individual developers who are not registered businesses, this means personal contact information is exposed publicly.
Since Calcoo is a free, open-source hobby project with no commercial intent, this requirement is disproportionate. Calcoo is therefore distributed directly from GitHub instead.