Why is oxaloacetate made in the mitochondria?
Got it.  The ratio of [NADH]/[NAD+] is about 100000 lower in the cytosol than it is in the mitochondria.  The conversion of malate to OAA reduces a molecule of NAD+ to NADH, and that NADH can be used for the later step in gluconeogenesis: the conversion of 1,3-bisphosphoglycerate to glyceraldehyde 3-phosphate requires a molecule of NADH.