A wrapper over what?? Bun includes the JavaScriptCore engine for JS evaluation, but it's so much more.

As for financial database concerns, if you're serious about including a project like that in your system, you have thorough correctness and performance testing stages before you commit to it. And once it passes the hurdles, at that point what difference does it make if it's written in a beta language, or a bunch of shell scripts in a trench coat, or whatever.