For whom?

For the audience - we love airplanes and love seeing them. I personally prefer the ground portion of air shows, where I can see and sometimes touch the airplanes up close, talk to the pilots and engineers, and generally have a nice day outside :). The aerial component is impressive too, depending on the show. Sometimes it's a bit drawn out.

For the organizers, typically it's a mix of profit and also organizer enthusiasm - a LOT of air show is basically hard-working volunteers.

For the participants, depends - the private entries are there for fun and visibility and showpersonship, cammarederie etc. The armed forces are there to promote and recruit and invoke patriotism and show off and impress.

Ultimately though, if airplanes aren't your kink, you probably won't emotionally / internally understand and that's ok. It's like world rally championship or formula 1 or anything redbull does, a risky entertaining spectacle.