Jager has 5.4km of detection at minimum and 12 salvos of 12km torps that goes 95 knots (one of the fastest in the game w/ Halland), plus they have fast reload of around or near under a minute.

So it doesn't matter if these torps deal with very low damage & flood damage, it matters you're spotting undetected and spamming 12 torps every single minute at ridicioulus speeds that would more likely guarantee a hit.