Would actually be quite impressive if it’s confirmed that NORAD is able to track and target a balloon/payload weighing between 11 grams-6 lbs, and flying between 30k-40k feet altitude.
They're just typically not used with such precision because of the sheer amount of false positives they'd generate and how little concern there typically is about something so small.
Navy guys claimed it could track a baseball in orbit.
But as Donald Rumsfeld famously said: "we can destroy a bomb placed under a pedestrian footbridge from 6,000 miles away without destroying the bridge."
So really, who knows.
aluminum has real advantages though
Is it really impressive? Modern stealth fighters have a radar signature smaller than small birds.