Those videos are staged. The signal playback trick doesn't work on newer cars because the code changes every time you lock or unlock your car. You could probably replicate the functionality of a key fob on your Flipper, but it would need to be registered with the car's computer the same as any other key fob, which means you'd already have to have to access to the car.
Signal playback doesn't require anything extra. I love that their docs have a giant warning to not use it on new cars though.