Even in that case, it's easier to understand the exception if you have a meaningful stack trace. A good promise implementation gives you that. Also, I guarante

Even in that case, it's easier to understand the exception if you have a meaningful stack trace. A good promise implementation gives you that. Also, I guarantee you will always get exceptions in production that you didn't see in development. Browsers are different, users do things you didn't think to test. If you care about quality, you need a system in place for reporting those exceptions back to the mothership, again including meaningful traces.