Those are pretty meh cantis, but the upgrade isn't critical per se. Unless we want to argue, for instance, that basically every vintage road bike in the world
desperately "needs" to have its brakes replaced as well.
a new saddle, fenders, water bottles, racks, bell, pannier bags, lights, computer etc etc
Those are standard switch-outs and additions that arguably shouldn't be counted. Most of them are the same things that could be applied to road bikes, but aren't in the OP's question.