Pad pitch flows down from the assembly house's capability
/ rules. Bond wire foot geometry sets pad size for wirebond
circuits, ball / column / pillar deformation, placement and
squish-out / residual min spacing for such assembly styles.
The foundries supply pads based on some customer demand
but if you don't look like those customers, you may have to
do some added work.
I truly doubt you have 0.48um pad pitch. Multiples of, maybe -
sounds like an arbitrary I/O-grid / -snap rule for reasons I
have no idea about.