If I rarely or never used high Iso with film, why should I care about high Iso performance for digital?
The answer depends upon why you rarely used high ISO with film. If you rarely had opportunity, need or reason to shoot in conditions that warrant high ISO, then perhaps high ISO performance really doesn’t matter for you. However, if you avoided high ISO situations because of the inconvenience and quality issues associated with high ISO shooting, then you might consider if a digital camera with good high ISO performance could expand the realm of situations in which you shoot.