What characteristics of DNA polymerase III make it an ideal enzyme for replicating the whole genome?

The key features of DNA polymerase III are its catalytic potency, its fidelity, and its processivity. It is able to catalyze the addition of ~103 bases per second, compared to only about 10 per second for DNA polymerase I,with an error frequency of about 1:104–105. One of the unique features of DNA polymerase III is its ability to continuously synthesize very long (thousands of bases) stretches of DNA, unlike DNA polymerase I. This is a consequence of its processivity; the β2 sliding clamps ensure that it remains bound to the template strand DNA.

In contrast, DNA polymerase I, without a sliding clamp, is much more likely to dissociate from the template strand after synthesis of short (tens of bases) stretches of DNA.