Should I run my tests against production build transforms (i.e. Babel)?

A coworker of mine recently setup testing in a new project (a JS library) where a transform step hooks in to the babel config for Webpack in the production config.

For reference, this is the setting used with Jest: https://jestjs.io/docs/en/configuration.html#transform-object-string-string

The production build targets ES5, while our CI is on Node 10 and up. This means that, for all of our tests, the source code is getting transformed by all the unnecessary Babel transforms. Mind you, our source code is regular ES2016 Javascript, nothing too fancy. The only transform required might be the ES6 import syntax.

My gut reaction was that this was quite wasteful and unnecessarily couples the tests to the production build config. But my coworker's justification was that he wants to make sure that the tests run against the same artifacts that users will be using.

That makes a lot of sense to me, but I am not sure what the right answer is. What are the pros and cons of each approach? What are the dangers of running your tests against the production build transforms?