Simply add the option of removing built in holidays to declutter and customize the calendar. Not everyone celebrates the same holidays and it visually clutters the calendar with events that aren’t necessarily needed by everyone. Or allow fine tuning settings for holiday preferences. Maybe someone wants to see all US holidays or maybe someone wants to see both US and Canadian holidays....or any number of combinations. Maybe even add options for lunar calendar events if anyone might need those. Basically include tons of info that is all editable, removable, optional. Maybe even have expansion packs for specific calendars like Farmers Almanac info, lunar cycle info, planting seasons, weather history. Being an accountant I wouldn’t need those necessarily but I do garden. My point is, people have many layers and so should their calendars. These days everyone uses smartphones, even farmers and ranchers. Customizing your calendars expands your market.