The pin description for DIN13/VS and DIN12/HS in the MAX96701 is a bit confusing and it should be explained like this. When the part is powered up, DIN13/VS and DIN12/HS pins are parallel inputs (DIN12 and DIN13). And after ~ 4ms, the chip starts initialization using the register settings. the pins become VS and HS if HVEN=1 . But it doesn’t matter, because the GMSL link takes ~7ms to be active. The inputs are "don’t care", because they are not used for anything until the link starts up.
This explanation is also applied to other parts in the MAX967xx family.