The 2.1 works in a similar way… I have the 2.1 and it has 16GB, so it records in a loop and captures the last 5 seconds of footage, and you press a trigger to stop it. Then it has a external SSD that is plugged into it and you save the clip onto there. It’s just a different type of system because you’re right, at such high frame rates and resolution it uses up a ton of storage space super quick. The FreeFly cameras have an internal 2TB SSD which I like better. But with high speed cameras you’re usually filming stuff that happens super quickly, so the 5 second rule isn’t too much of an issue. Some phantom cameras can only do like 2 seconds.
It is affordable per say if you’re in that market (I am so I know it well.) A phantom high speed camera that can do 30,000 FPS, which is one of your only other options, can run $80-200K. These aren’t cameras that the average person gets to just shoot a few slow mo clips and have fun. They’re for research, filmmakers, and YouTubers who film explosions and other super fast stuff.