Chucks are commonly regarded in the woodworking world as the go-to method of holding work on a lathe when creating a bowl or platter. Typically they are four-jaw, self-centering devices that grasp the work by a tenon or recess. They hold the work very securely and are quick to use, however they mar the work in some way that must be repaired, usually requiring a jam chuck.
Jam chucks offer the ability to hold work without marking it, but they take yet another piece of wood and require sometimes a fair bit of time to create. The best of both worlds, vacuum chucks hold the work without marring it and the work can be set up as quickly as a normal chuck.
Better yet, can you imagine how the natural-edge bowl in the photos below could be held by any other means while working on the foot?
I know of at least one woodturning artist who uses vacuum chucks exclusively for his multi-centered pieces, not just for holding a piece to finish the foot, switching rapidly between placements. Vacuum chucks are capable of holding work that requires serious wood removal. Creating a jam chuck to hold this bowl to finish turn the foot would be very involved and probably take longer to create than the bowl itself.