It's like a fly sitting on the windshield of your car parked in the driveway or something. It's there, it might be annoying if you think about it, but it isn't actually doing any meaningful harm.
I haven't yet seen a compelling reason to think it is either Chinese or an espionage craft anyway,other than news reporting "the Pentagon sure thinks so"
"Letting it sit", the "it" being what they're calling a "surveillance" balloon, seems absurd. If we have an ongoing MITM attack, we need to stop the attack, not simply observe it like idiots.
It's like a fly sitting on the windshield of your car parked in the driveway or something. It's there, it might be annoying if you think about it, but it isn't actually doing any meaningful harm.