^^^The big deal is that based on the results of the PSA, patients may undergo an unnecessary biopsy or further treatment, all of which have their own costs and potential risks. You have to weigh the biopsy and further treatment against the patient's age and medical condition. For many men, prostate cancer is diagnosed at an age such that they will likely die of something else before the prostate cancer effects them.
I was reading the chart just yesterday of a patient who died of metastatic prostate cancer at age 59, two years older than me. They found it by chance two years ago: he was referred to urology for flank pain, and as part of the workup, they did a PSA which was elevated, and then did further imaging and a biopsy which confirmed the prostate cancer. He ended up having surgery and radiation but still died two years after diagnosis.