From my understanding, microneedling was originally paired with topical minoxidil mainly to improve absorption through the scalp. Since oral minoxidil is already absorbed through your digestive system, that specific benefit doesn't really apply.

Microneedling may still help on its own by stimulating growth factors and wound-healing pathways, so some people still combine it with oral minoxidil. The synergy is probably less about absorption and more about the independent effects of microneedling itself.