How Does Timecode Vinyl Work? (Pt. 3) (mixxx.org)

This is for that DJ thing where DJs use record players which use dummy records that just have position info, I think. Then that data is fed to something that indexes into the audio file, giving the illusion of DJ spinning and scratching effects. This allows DJs to pretend they are using "vinyl". Is that right?

Are timecode vinyls cheaper than encoding the rotation of the disc directly be the player? Is it for backwards compatibility with old players?