Every television on the market has an OTA tuner onboard, even if most people never use it. If it doesn't have one then it's a monitor -- the tuner is the essential difference. The advent of smart TV means that cord-cutters can now connect directly to the internet and get on-demand streaming, as well as live TV. Streaming usually costs a subscription fee, while an antenna can receive free signals and without an internet connection. While you don't need an antenna to use smart TV, the two do complement each other very well.