Interestingly, science fiction author H. Beam Piper explores this concept in his book Last Enemy, published in 1950. It's quite interesting and a very good read. Here's a free link ..
https://www.gutenberg.org/ebooks/18800
Excellent point. In life, we have to go by laws made up by people, which allow some to spend freely and then renege on their promise to pay. Reincarnation would go by some natural law, so those trying monetize usury would probably not only be bugs, but the kind that gets preyed on by other bugs.
https://www.gutenberg.org/ebooks/18800