I wasn't seriously suggesting using the automotive pack, the main benefit to the 4680 is the tabless design which significantly lowers internal resistance and increases the power output [I seem to remember a video of an aerospace supplier (for fighter jets?) making cells with similar style electrodes]

The 4680 is also the cell format not necessarily the chemistry nor pack design.
While presumably they might want a chemistry tolerant of high-C charge/discharge cycles with minimal degradation, at this point it might not be that important as the booster won't likely have a long service life (maybe even only one flight), so the number of cycles will presumably be very low.