I saw the phrase, “on the debit side” and “on good part” as a contrast in the following sentence of New York Time’s (December 17) article titled “Life Goes On, and ON,” that deals with the opportunities and problems of longevity society:
“Is this (extended longevity) a good thing or a bad thing? On the debit side, there’s the ... debit. The old-age safety net is already frayed. According to some estimates, Social Security benefits will run out by 2037; Medicare insurance is guaranteed only through 2024. These projected shortfalls are in part the unintended consequence of the American health fetish. ---
So what’s the good part? Time spent with an elderly parent can offer an opportunity for the resolution of “unfinished business,” a chance to indulge in last-act candor. ... I hear a lot about late-in-life bonding between parent and child."
Obviously “on the debit side” is used in the sense of “on the negative side,” and “good part” for “on the positive side.”
Can I use “credit side,” the antonym of “debit side” instead of “on the positive side / on the good part” in the above sentence? I mean, can I rephrase the last line as “So what’s the credit side? Time spent with an elderly parent can offer an opportunity...”? Or is the word, “credit side” only applicable to bookkeeping?