ACNH has a robust modding community. Repacks are often used as the base for installing mods—ranging from custom furniture to entirely new gameplay mechanics—without risking the banning of a legitimate console. This freedom to experiment is impossible on a standard, online-connected Switch.
If you are looking for the definitive Animal Crossing experience, ensure your version includes the 2.0.0 "Big Update" features: animal crossing: new horizons repack