Those good old times are long gone when buyers were looking for properties in newspaper advertisements or calling real estate agents based on telephone books. These methods had been replaced by online searching so it is essential for an agency to be present on the social media platforms and use the online and offline possibilities given by 21st century.
Unless you are going for the ultimate and most expensive smart home setup, you don't need to spend all your monthly income on buying lots of components, sensors, smart bulbs, security cameras, etc., since for most users, it would be overkill anyway.