There is no confirmation that Kavanaugh spent $200k. That figure come from the top limit of a given threshold off a financial questionnaire. When you read something along the lines of "so and so had between $45,000 and $150,000 in credit card debt" that's an indication that someone checked off a box that says "Credit card debt - Less than $45k, between $45k-$150k, $150k-$300k, etc. Please check off which it is" kind of thing.
"Between $45k and $150k" does not mean "$150k...maybe more because he's obviously hiding stuff!!". It could mean $45,001.00. It could mean $63,264.28. All you
know from "between $45k-150k" is that the number probably fits in that range somewhere. Anything else you think you "know" is speculation unless it's supported by other facts and other information.
Now, getting back to the hyperventilating, if I knew that I could spend $100k on Washington Nationals tickets, go to a dozen games or so and sell the remaining tickets for $120k I'd do that because it makes good financial sense. Likewise, if I had a group coming to town and they wanted game tickets I might well put those tickets on my credit card and then pay the balance off when the group reimbursed me.
Now then, as far as such arrangements being "fairly common" I would ask that you take this article from CNBC -
https://www.cnbc.com/2015/03/04/online-ticket-resellers-the-surreptitious-rise-of-the-online-scalper.html - as an indication of how common the arrangement is. The article (from 2015) cites a $5 Billion industry in this kind of thing. It is, by all reasonable measures, "fairly common".