I'm not a radar expert, but maybe someone who is can enlighten us?
They can detect an incoming missile, so I don't see the problem. Maybe the one today IS a lot smaller; I don't think we're getting a whole lot of details on that.
As for the money: definitely. The same would be true of drones.
From someone that has done a much smaller balloon launch, it's not the balloon that gets detected as much as the payload. Our civilian weather balloon launch had a metallic reflector in line specifically to make it more visible on radar. The images I've seen of the payload under the large balloon from last week didn't look all that stealthy in shape, but I have no idea what it was made from? If it was made of plastic, would that reflect radar?
The USAF (and any functional air force) has lots of flight time budgeted for its pilots: for training, patrols, etc.
Active duty pilots must fly X number of hours per month to maintain their fight status. Essentially, they practice like athletes (because they are literally athletes, among other things)
So intercepts like these, and even silly stuff like sports event flyovers, come out of their existing budgets.
To actually cost us money in some meaningful way they'd have to send over extremely large quantities of drones that absolutely blow out the existing budgets for our bases.
The missiles are expensive, of course: $400K a pop for those AIM-9X. But the budget for the USAF is ~$160B/year, so again, drop in the bucket.
So far they're offering good sport for the USAF. I'm glad they decided to take action and shoot'em down instead of letting them pass undisturbed through US airspace. This should send a clear message to uncle Xi to keep his lantern festival at home.
Then stop using expensive missiles to pop a balloon. Are we so scared of a balloon to get into gun range? A short burst of 20mm would be pretty cheap compared to an AIM-9
Ordinance has a best used by if not a shelf life. Use it or lose it probably matters to someone.
Missiles can detonate near a painted target, instead of needing direct contact. If the thing being exploded is hazardous (when exploded), you don't want to be flying nearby.
This is not an exercise. Combat time is valuable, even if shooting down drones/balloons.
Politically popular optics. Everyone likes a boom, just to be sure. What happens if it falls to the ground and on to someone or someone grabs the wreckage or worse, it's never found? Bad optics.
The common tactic of dismissing high stakes situations as idiotic, is intellectually lazy.
I was wondering if modern planes even still had ballistic weapons, since engagement range for missiles is measured in miles. For anyone else wondering, according to [0] they still have guns, since most missiles have a minimum engagement range so there is still a need for short range weapons.
My understanding is that these UAFs are much smaller than that first Chinese balloon last week.
It probably also costs a lot more money to shoot down a balloon than it costs China to put a balloon in the air.