Many libraries and applications use exceptions as control flow or data collection, which allows for handling complex situations with more consistent and legible code. Some libraries use custom throwables (IGJoshua/farolero, NoahTheDuke/lazytest) and some use ExceptionInfos (scgilardi/slingshot, fmnoise/flow, pangloss/pure-conditioning, exoscale/ex).
One of the reasons that libraries reach for custom throwables is because they want to skip creation of a stack trace (which isn't used and would be thrown away immediately). Stack traces in Java are already fairly expensive to create, and then the filtering work done in ExceptionInfo greatly increases that expense, making them much slower than needed. (There's an Ask about this but I can't find it.) This performance cost pressures developers to use custom throwables if their code will ever be used in a "hot path", which harms portability and ease of development. (I want to write Clojure, not Java, and I want it to be usable in Clojurescript and Babashka and whatever other dialects might arise.)
I know that there's a rejected Jira ticket (CLJ-2423) for supporting the "enableSuppression" flag, but in light of these use-cases, I'd like to bring it up again.
