What is the importance on transformer utilization factor?

Ulitization factor is how much of the designed total is used. My house is fed off a 50KVA transformer. It's capable of supplying 50KVA continuously, but it's probably only gets used at its' full potential every once in awhile (when my neighbors and I wake up in the morning, and when we get home from work and eat dinner, perhaps). Say it only gets used at 30KVA on average. The utilization factor would be 30/50, or 60%.