The Shulchan Aruch states the meals on Chanuka are (only) permissible feasts (not seudas mitzvah) since these days were never instituted as days of festive meals. The Ramma quotes an opinion stating the meals have some mitzvah associated with them as the Mizbeach was inaugurated in those days.
ריבוי הסעודות שמרבים בהם הם סעודות הרשות שלא קבעום למשתה ושמחה: הגה וי"א שיש קצת מצוה בריבוי הסעודות משום דבאותן הימים היה חנוכת המזבח [מהר"א מפראג]
I am confused. Nobody argued that the miracle of the oil was insignificant and therefore the meals are not a seudas mitzvah. It was a wondrous event. There happened to be a technicality that they were not instituted as such. Why they weren't is irrelevant. How does mentioning another momentous occasion in those days help? There is no statement mentioning they were in fact instituted as days for festive meals, so what have we gained with mentioning the Mizbeach's inauguration over the Menorah's miraculous oil?