HOME ASSISTANT as a system simply means making your home digital and being a personal assistant to you

It is digitizing of the home, housework or household activity.
It includes centralized control of appliances, your daily schedule, communication system, and inventory management.
It will work as an assistant to your needs and to your personal life. It will be an interactive device to which you will be able to talk and converse and can also assign tasks to remind you or keep in a database.
It can be used to increase the security of your house by using face recognition techniques as well as motion sensor and alerting system. It can act as mode of communication between two rooms or multiple rooms.
It will be able to learn from the environment and act accordingly. Inventory management is also implemented in this system which will be able to alert you about the things you are running low at your place.