RFBA catches people by surprise because exempt benefits can still be reportable: an FBT-exempt electric car still generates an RFBA. The amount does not add to taxable income, but it feeds means tests such as study loan repayments, child support and some government benefits.
Employers need per-employee benefit values to report it, which is another reason per-vehicle, per-driver records matter. See fringe benefits tax.
General information, not tax or legal advice.