I wouldn't put that in the same category as campaign donations. That money won't help the candidate get elected. The money goes to the inaugural committee to pay for the event.

I'd put that in the broader category of doing something the president/politician likes in hopes of gaining favor.

With this administration there are even better ways to gain influence and money by doing things the president likes than donating to inauguration ceremonies. Become a known staunch Trump advocate, and you could become the Secretary of Defense, FBI Deputy Director, or head of DOGE. No experience necessary.