A smart home is one system, not a drawer full of apps
Most homes end up with smart devices rather than a smart home. The lights use one app, the cameras use another, the heating has its own remote, and nothing knows what anything else is doing. Every device works, and yet the house is no easier to live in than it was before.
A smart home is what you get when all of it answers to a single system. The house knows whether anyone is home, whether it is dark, whether rain is coming, and whether you are asleep. Once it knows those things, it can act on them without being asked.